Nobody thought anyone would jump back-first in the Olympic high jump until 1968, when Dick Fosbury invented the Fosbury Flop. Although initially shunned, there was no rule to forbid it. Today it is the dominant style in high jump.
The barra vasca style in Olympic javelin. It is basically throwing javeling as if it was a discus. The grip is inverse, and the thrower spins a couple of times like a ballet dancer before ejecting the javelin. It is based on old Basque style of war javelin. The Spaniards under Francisco Franco invented the style to break the Finnish dominance in javelin in 1956. The rules didn't exactly say you have to throw the javelin overarm, and barra vasca appeared to be an immensely effective style; the stick could well fly over 100 m. Unfortunately it was also notoriously inaccurate - and dangerous: only three throws in four actually landed on the sector, and as one Spaniard had thrown the javelin into the grandstand, the style was quickly prohibited before the Melbourne olympics 1956.
Race car driver Smokey Yunick was so notorious for this that some automotive journalists call this trope in auto racing "Yunicking the Rules." For example, when NASCAR rules tried to force more pit stops by limiting the size of the gas tank, Smokey replaced his fuel lines with exhaust pipe, adding several more gallons that technically were not part of the fuel tank. "If you ain't cheatin', you ain't tryin'." is practically the unofficial slogan of NASCAR; Yunick just took that to the natural extreme. Other tricks over the years included finding various places in the cars to hide lead ballast so the vehicle would meet mandated weight minimums, and then jettison it before the race, making the car lighter.
This is why NASCAR and all other organized motorsports have blanket "Actions detrimental to racing" rules which they cite with every infraction anyway to keep people from trying to find clever ways to alter their equipment that isn't specifically cited as illegal but is against the spirit of fair play.
NASCAR has also had some other notorious examples of this abuse: In the 1997 All-Star race, Hendrick Motorsports built a special car for Jeff Gordon, nicknamed "T-Rex" after lead engineer Rex Stump (coincidentally, it was sponsored by Jurassic Park: The Ride), which was entirely inside the rulebook at the time, but exploited every gray area that rulebook contained. The car ended up being a full second faster than any other car in existence at the time, including the other cars in Gordon's stablenote keep in mind, he won ten races and the Cup that year, and he ultimately flattened the rest of the field in the race. NASCAR called Rick Hendrick into the office a few days later and told him that T-Rex's setup would be illegal for the Coke 600 and all further races, and shortly after issued a new, far thicker rulebook to prevent further "experimentation".
In the 2002 All-Star race, drivers had to make a pit stop during the first segment. Jeff Burton made his on the 40th of 40 laps, which was possible only because he was assigned the pit stall that was before the start/finish line, and so he had to drive a much shorter distance at pit road speed limit. Subsequent versions of this rule included a specific lap for the stop, in order to close this loophole.
Jimmie Johnson and Chad Knaus have been accused of abusing a grey zone in the 2012 rear suspension package, to "yaw" the rear end out to a substantial extent, which has allowed him superior handling and speed in the race. These complaints reached a peak at the Brickyard 400, where Johnson led 99 of 160 laps and won by nearly five seconds. About a month later, NASCAR tightened the rules concerning this grey zone to cut down on such abuse.
It's worth noting that Johnson wasn't the only one working in this area - "yawing" or "skewing" the car out was a very common tactic to try to increase side force and get better grip in the turns, with the universal indicator of this being "dog-tracking", where the rear-end of the car would slant to the left, leaving a substantial amount of spoiler directly exposed to the air. It could be seen on practically every car in the field in 2012 - it just so happens that Johnson and Hendrick were ahead of the field on this, as they so often are. NASCAR took further steps to minimize skew in the Gen-6 Car, by removing the components which the teams were experimenting with in the first place - and the penalties given to Penske's drivers Brad Keselowski and Joey Logano at Texas were due to the pre-race inspection failure of parts that would've allowed them to skew the rear ends.
Formula One also has many example of creative interpretation of the rules, especially getting around the rules against 'moveable aerodynamic devices' - over the years teams have tried flexible wings and floors that bend in the wind and reduce drag; the Brabham team built the infamous 'Fan Car' where a so-called "Cooling Fan" created a vacuum under the car. In 1981 minimum ride height rules were introduced, to be policed by random checks in the pits. Brabham's Gordon Murray designed a hydraulic suspension system that raised the car in the pit lane (when it was being checked) and lowered it down again on the track. Lotus built the Type 88 double-chassis car, where the top chassis would lower down onto the track at speed creating ground effect suction. Ironically it was the more ingenious Lotus that ended up being banned. More recently in 2009 Brawn GP got round the rule specifying a 'single deck' rear aerodynamic diffuser by incorporating the mandatory rear crash structure into the diffuser, thus generating more rear downforce. In 2010 McLaren built a duct into their car that the driver could operate with his elbow (!); when used on a straight the duct stalled the rear wing and reduced drag.
That trick was banned by FIA in the 2012 rules by an Obvious Rule Patch- which forced the drivers to keep the hands on the steering wheel at all times. So Mercedes (the successor of Brawn) kept the duct but made it so it could be activated from the wheel, using the same button that already existed for the DRS system.
Played straight, then averted for Tyrrell in 1984. Formula One rules dictate a minimum weight all cars must meet, but at the time it was common to find ways to reduce the weight of the car while on the track (and unable to be weighed) such as water cooled brakes that were fed by a reservoir, which would gradually empty throughout the race, shedding weight, and be topped up to pass inspection.
Tyrrell was the only team with a normally aspirated engine that year, every other team having the dominant turbocharged monsters, and were only earning points due to luck and the skill of their drivers (Martin Brundle and Stefan Bellof.) However, this gave them some leverage against the turbo-running teams, as fuel tank sizes were to be cut to 195 liters (from 220L) in 1985 to curtail the power of the turbo cars. Every turbo team would vote against it (as the turbo engines guzzled fuel,) but to scrap it, they needed a unanimous decision, leaving Tyrrell (with the vastly more efficient n/a engines) in the way, leverage they were more than willing to use.
Tyrrell used a water injection system for their engines, clawing back a little of the power deficit that would be topped up before the race ended with two gallons of water, and 140 lbs of lead shot. The FIA, after inspecting the system, eventually ruled that the water in the tank consisted of 27.5% aromatics, constituted to be an (illegal) addition fuel source, as well as illegally taking on addition fuel during the race, illegal fuel (the water/lead mix,) illegal fuel lines (the lines to the engine,) and improperly secured ballast (the lead shot.) As a result, the FIA excluded Tyrrell from the championship that year, and retroactively disqualified them from all races that year. However, additional testing showed the water carried well below 1% aromatics, and thus well within the rules. Tyrrell also argued that the rules required that ballast be fixed as to require tools to remove, which they felt was the case for the lead shot trapped in the tank. As such, they went to appeal. In an unbelievably draconian move, the FIA ignored the test results, changed the charges to fuel in the water and illegal ballast, and then added a new charge of illegal vents in the undertray, claiming they violated rules preventing the use of ground effect, but where eventually found to be of no aerodynamic purpose. Oh, and the exclusion was upheld, and a further ban from the final three race was instituted, incurring an additional fine for missing those races. This ended up being a double-whammy for Tyrrell, as the turbo teams were now free to amend the rules as they wished, while Tyrrell scrambled to secure a deal for turbo engines for 1985, and also lost all their points for the championship, losing the subsidized travel costs their points haul would have earned them, an addition cost.
Another classic rule bend came from F1's near cousin Indycar (back before the 'Split' and today's spec series, when teams often built their own cars). 1994 Indy 500 rules allowed pushrod engines higher turbo boost levels, ostensibly to encourage engines based on road car engines. Except nothing in the rule book actually specified the need for a stock block, so Penske Racing commissioned a custom Ilmor-Mercedes pushod engine that pumped out 200hp more than rivals and walked the race.
Texas oilman, race car driver and engineer Jim Hall was the creator of Chapparal Cars and created the legendary Can-Am monster, the 2J. At the time there were no rules that prohibited a Can-Am racing car from having more than one engine, so he took a Chevy V-8 and powered the boxy 2J's rear wheels with it and took a snowmobile engine to power a set of rear-mounted fans to suck the car to the ground with. When it wasn't broken down it was an amazing car, and when it wasn't broken down or winning, it was being banned.
In an effort to speed up the games, the NCAA changed the clock rule on kickoffs, causing it to begin running when kicked instead of when it was touched. The University of Wisconsin scored a TD with 23 seconds left in the first half, and deliberately went offsides on the subsequent kickoff. Each time the play was run, they would be penalized and have to do it again, but it would take 5 seconds off the clock that were not replaced.
One of the most famous sports examples was the notorious 1994 Barbados vs Grenada soccer game. Barbados needed to win by 2 clear goals to advance to the tournament final, but were only winning 2-1 in the final minutes of the game. The tournament rules stated that a draw would go to sudden death extra time, and the winner would be deemed to have won by two goals. After Grenada scored late in the game, the Barbados team realized they'd be unlikely to score as Grenada would play defensively since they didn't need to win, only to not lose by more than a goal. So Barbados fired the ball into their own net, levelling the score, then clustered around the Grenadan net so they couldn't do the same thing. Time runs out, game goes to sudden death extra time where Barbados wins.
The Underarm bowling incident of 1981 caused a major Cricket scandal when a one day international between Australia and New Zealand came down to the last ball of the New Zealand innings. With New Zealand able to tie the game by scoring a Six, the Australian Captain realized that Underarm Bowling (a completely anachronistic practice of rolling the ball along the ground instead of the usual bounce method) had not been stipulated against in the tournament rules. While a rolled ball is easy to put into play, it is nearly impossible to score a Six, therefore robbing New Zealand of any chance to win the game. While Australia won it was widely viewed in both countries as ungentlemanly cowardice. As a direct result of the incident, underarm bowling was banned in limited overs cricket by the International Cricket Council as "not within the spirit of the game".
In American High School Football the A-11 offense exploited a loophole in scrimmage kick formations that allowed all players to be numbered as eligible receivers, thus disguising who the actual receivers were and expanding the number of plays the defense had to defend against from 250 to 16,000. Cue Obvious Rule Patch two years later (though Texas and Massachusetts use NCAA rules, which never allowed the thing in the first place).
John Hopoate, a player in Australia's National Rugby League, became notorious for using a rather unorthodox move to make other players more likely to fumble during tackles. Turns out there wasn't any rule saying you aren't allowed to jam your fingers up another player's bum, and in the end the NRL had to declare him guilty of conduct unbecoming the game before they could get rid of him.
Unfortunately for Hopoate, however, it turns out that although there wasn't any rule in rugby specifically banning inserting your finger in someone's anus, Australia's criminal law regards it as a form of sexual assault (which, you know, it kind of is). Sure enough, Hopoate was charged with unlawful sexual conduct after the incident.
George Burns and Harpo Marx were once playing golf on a very hot day, and decided to take their shirts off. A nearby group complained, and the club manager came out to inform them that club rules required them to wear shirts on the course. A little while later, he received another complaint - this time they were playing without pants. When he went out to tell them to put pants on, they asked to see the rulebook on that - and it turned out that there was no rule requiring club members to wear pants on the course, because nobody had ever thought to need it.
Golf is a minefield for loophole-lovers. The general rule is, if you try to use the Rules Of Golf to your advantage, you better make damn sure you know what they are. Because your opponent will. (And in any important case, one can always drag out the Book and/or the official.) Excellent fictional example: "The Foursome", by "Troon McAllister".
The downs system of American football and basketball's shot clock were added when teams took advantage of the lack of such a rule to simply indefinitely keep possession of the ball. Sometimes these "keep away" tactics got really bad; on November 22, 1950, a basketball game between the Fort Wayne Pistons and Minneapolis Lakers ended in a score of 19-18note That game is officially the lowest score in a NBA game. Since there's a shot clock in the modern game, it is now impossible to beat this record. Another 1950 game went for six overtimes, with each team only taking one shot in each extra period.
College basketball didn't adopt a shot clock until 1985, after "stall ball" became a semi-common strategy for underdogs trying to even things out against more talented teams. The most notorious example was in 1973 when Tennessee defeated Temple 11-6, in a game where Temple held the ball for over 32 minutes (out of 40). Even now you still see it in high school ball (only 8 states use a shot clock).
At the time of the infamous "Snowplow Game" in 1982 between the Miami Dolphins and the New England Patriots, there really wasn't a rule you couldn't plow a section of the field in football before a field goal. Needless to say, after the game there was one. This game, by the way, is the real reason why Dolphins fans gloat so much over New England's failure to complete a perfect season.
It didn't hurt that Don Shula was a member of the NFL's rules committee. This probably produced his familiarity with the rules that allowed him to see that there ain't no rule that says you can't fool the defense into thinking the play's over by pretending to spike the ball to stop the clock, and then pass the ball to an eligible receiver - New York Jets fans remember this as the 1994 Clock Play. And it's still a legal play (as it would be nigh-impossible to patch).
Football lovesLoophole Abuse, and several plays depend on it. (Generally, only the most blatant exploits are the ones that get patched; if an exploit is more trouble to patch than it's worth, or doesn't really cause too much harm to the game for whatever reason, it will become part of the game.) There's no rule that the quarterback has to be the player to receive the snap, giving rise to "Direct Snap" plays that give the ball from the center to the running back with no hand-off. There are rules that state that only certain positions are eligible receivers, but there's no rule that says they can't then pass the ball to someone behind them (even an ineligible receiver; the rules specifically prevent forward passes and forward handoffs to ineligibles). There's a rule that says that the kickoff must be kicked at least ten yards or touch a member of the receiving team in order for the kicking team to take possession without ending the play, but there's no rule that says you can't kick the ball directly at one of the close members of the receiving team and get the ball when it inevitably bounces off him.
Back when Carlisle Indian Industrial School had a football team in the early 20th century, they were notorious for exploiting the holes in the rulebook. One tactic was to have leather football patches sewn onto every uniform so that every player appeared to be carrying the ball, since there wasn't a rule prohibiting it. They were stopped by Harvard, who when they played Carlisle presented game balls that had been dyed a deep crimson color (since there wasn't a rule against that either) to neutralize the trick. Naturally, both of these cases were inevitably patched.
One of the classic examples in football is the infamous "Holy Roller" play (also known as the "Immaculate Deception"), run by the Oakland Raiders (who historically don't have the best of relationships with the rules) in a 1978 regular-season game against division rival San Diego. With 10 seconds left in the game, the Raiders had possession of the ball at the Chargers' 14-yard line, trailing 20-14. Raiders quarterback Ken Stabler found himself about to be sacked. Stabler fumbled the ball forward. Raiders running back Pete Banaszak appeared to try to recover the ball on the 12-yard line, but could not keep his footing, and pitched the ball with both hands even closer to the end zone. Raiders tight end Dave Casper was the next player to reach the ball but he also evidently could not get a handle on it. He batted and kicked the ball into the end zone, where he fell on it for the game-tying touchdown as time ran out. During the play, the game officials ruled that Banaszak and Casper's actions were legal because it was impossible to determine if Stabler intentionally fumbled the ball forward (which is—and was—considered a forward pass; the play would be considered dead when the ball hit the ground) or if the players batted the ball forward (which is—and was—illegal in this case; the penalty would have negated the score). This lead to an Obvious Rule Patch dramatically limiting what offensive players can do in terms of recovering fumbles. Stabler, Banaszak and Casper all admitted after the fact that they had indeed deliberately fumbled and deliberately batted the ball forward, respectively. But it's Not Cheating Unless You Get Caught.
Football has several rules to cover "Palpably Unfair Acts," which serves as a Rule Zero when something blatantly unfair happens that isn't covered by the rules (or if applying the rules strictly would still greatly benefit the offending team). It isn't applied often, though. Amusingly, the first time someone ran off the sidelines to tackle a runner, everyone agreed that the referee could award a touchdown even though the rule patch didn't exist yet. Under the current rules, the referee can award anything he deems necessary to negate the advantage a team gained by cheating overt enough to merit a "Palpably Unfair Act" penalty. Up to and including declaring the offending team to have forfeited (except in the NFL, where the penalties are specifically limited to yardage and scoring).
In college football, missed field goals used to be considered touchbacks and the opposing team would start possession on the 20-yard line. So in certain situations teams began opting for ridiculously long field goals instead of punts, since it was a no-lose proposition: you could luck out and make the FG, but if you missed you pinned the other team deep in their own territory and didn't have to worry about punt returns. After a rash of successful 60+ yard field goals in 1976 and 1977 (including the still-standing Division I record of 67 yards and all-divisions record of 69 yards), the rule was changed to award the other team possession at the line of scrimmage of the missed FG.
There was no rule in cricket about bodyline bowling, where the fielding team repeatedly bowls fast short deliveries aimed at the batsman's body, whilst setting a field with a high number of close legside catchers in the hope of catching deflections when the batsman defends himself. The England cricket team used this method to counteract the success of the great Australian batsman Sir Donald Bradman during the 1932-33 Ashes. After the infamous tour bodyline was effectively banned by changing the Laws of Cricket to limit the number of fielders allowed behind square leg, and adding that "The bowling of fast short pitched balls is dangerous and unfair if the umpire at the bowler's end considers that by their repetition and taking into account their length, height and direction they are likely to inflict physical injury on the striker."
Again in cricket, the ball must be bowled, not merely thrown. Originally, this meant underarm. But there was no specific rule against round-arm bowling. The loophole was closed after John Willes (supposedly) tried it. Then re-opened, when the rules were changed to allow it.
Eventually, the rules were changed to allow overarm bowlingnote but you mustn't straighten your arm, which quickly became the only method used. Except in 1981, when Australia's Trevor Chappel bowled a technically legal underarm delivery, rolling the ball along the ground to prevent the batting side hitting a six off the last ball and tying the match. Underarm bowling is now prohibited.
The captain of the batting team was facing the first ball of the innings, with the opposing captain as wicketkeeper. The ball was almost a wide down the leg side, but broke back viciously and bowled him out. The astonished batsman exclaimed, "Well, I declare!" The opposing captain overheard and took him at his word, so the innings was closed at one for naught. After the teams changed round, the first bowler began running round and round the boundary with no apparent intention of stopping. When asked what was going on, the captain of the fielding side explained to the umpire, "There is no rule limiting the length of the bowler's run. He's the local marathon champion, and he's running until bad light stops play". The match was drawn with one ball bowled.
This is an essential part of nine-ball pool. The balls are numbered from 1 to 9, the rules state that you must strike the lowest-numbered ball on the table, and the winner is the player who pots the 9-ball. This implies that the intent is to first pot the 1-ball, then the 2-ball, then the 3-ball, and so on until you pot the 9-ball and win. However, there Ain't No Rule saying the balls must be potted in order, so play often involves striking the lowest-numbered ball into the 9-ball and attempting to pot the 9-ball, or into any other ball to keep shooting.
This is also used as a tactical move when you can't easily pot any ball by hitting the lowest first. If you don't hit the lowest ball, the other player can place the cue ball anywhere on the table which usually means a setup for an easy shot. If you do hit the lowest but don't pot anything, the other player will have to shoot from where the cue ball ends up, which ideally is in a position where they will foul and you'll get the cue ball back anywhere on the table. In some games you can get the players making incredibly accurate finesse shots one after the other trying to get the other to foul.
Some variations even cause a player to lose if they foul three times in a row, leading to even greater abuse.
At one of the Winter Olympics, Canadian Skiers didn't know there was a rule against "tobogganing", or slowing yourself using your bottom. When they did this, other athletes immediately complained to the judges, who opened that year's rulebook to cite against this maneuver — and discovered it had been accidentally omitted...
Likewise, in the 1984 Sarajevo Winter Olympics, ain't no rule you can't prolong your dance by not touching the ice with your skates for the first eighteen seconds. Said loophole abuse resulted in the only perfect-scoring ice dance in the history of the Olympics: Torvill and Dean's "Boléro". "Boléro" itself is 17 minutes long. They managed to cut the song down to 4:28, 18 seconds longer than the Olympic rules. Since actual timing starts when the skates touch the ice, they went with Loophole Abuse. This is now against the rules. Though ice dance in general is prone to teams creating unusual moves, where there ain't no rule, leading to next season there being a rule.
Another Olympics one: Canadian Ross Rebagliati was stripped of his gold medal when traces of marijuana were found in his system. However, marijuana wasn't actually on the banned substances list, so they gave it back to him. Then again, marijuana isn't exactly a performance enhancing drug.
Robin Williams (commenting on the incident years later): "Marijuana enhances many things, colors, flavors, sensations, but you are certainly not f**king empowered. When you're stoned, you're lucky if you can find your own goddamn feet. The only way it's a performance-enhancing drug is if there's a big f**king Hershey bar at the end of the run."
There may be a rule in baseball and softball about teammates assisting a runner, but there's not one about opponents assisting a runner...which led to a Crowning Moment of Heartwarming when college softballer Sara Tucholsky hit the only home run of her career, but tore her ACL rounding first. Two members of the opposing team carried her around the bases so her home run would count. (More complete summary at the Real Life CMOH page)
While it definitely qualifies as a CMOH, the umpire was actually wrong. There was no rule that would have prevented her teammates from assisting her around the base path, as it was technically a home run as soon as the ball cleared the wall, which used a different, reduced set of base running rules. (Mainly that you're still out if you pass a runner ahead of you). Still, it makes a better story the way it happened.
Also, if somebody hits an actual bona fide home run then they're quite likely to want to run the bases, whether it technically has to be done or not. It probably wouldn't feel right, otherwise.
To score a run in baseball, you have to tag home base. Practically everyone thinks of this as tagging the base with your foot, and that therefore if the catcher is already in the way you can't really tag home. But there ain't no rule that says you have to use your feet. During a college baseball game, Fordham player Brian Konwnacki took this to almost gravity defying levels when he jumps over the catcher to get to home plate and makes a flawless flip onto home plate to score a run.
This "loophole" is evident to anyone who's ever seen a player execute a headfirst slide. Or dive toward a base on a pickoff play. The reason many people consider a move like the above clip unusual is that the most convenient way to touch a base is usually with the foot. Also, leading with the arm or head is more likely to result in you injured and out.
Also, from that same clip, ain't no rule that says you can't steal third base when no one's looking. (About 1:05 in the clip.)
If a player is arguing with the umpire, time is not automatically out. This has happened more than once in the major leagues; one notable example occurred when pitcher David Cone contested a safe call, and two base runners scored while his back was turned.
An interesting example from 1963 involved a player named Jimmy Piersall, who was known as something of a Cloudcuckoolander. Piersall celebrated his hundrenth career home run by running the bases facing backwards. (That is, backpedaling from home plate to first, first to second, etc.) This was done on a bet with one of Piersall's teammates. No rule could be found forbidding this action, so the run was counted. The Jimmy Piersall rule was put into force following this event as an Obvious Rule Patch.
Eddie the Eagle utilized a loophole allowing every nation to send a representative for every sport. At the time, nobody else from the UK entered for ski jumping, so Eddie did and was legally allowed to compete. Obvious Rule Patch followed requiring all competitors to have won an international competition previously or be in a certain top percentage in their event. This is even portrayed in his biopic Eddie The Eagle
In combat sports, a title cannot change hands unless it is contested within its weight class - if either competitor is overweight, even if the challenger wins, the title remains with the champion. Several champions, expecting to lose, have come in overweight, lost, and retained the title. Like Paulo Filho, then of WEC.
The World Boxing Association (one of the Big 4 sanctioning bodies) since closed this loophole with Rule 2.5, part of which states that if the champion fails to make weight, he loses his title "on the scales" regardless of the match's outcome.
National Hockey League coach Roger Neilson was infamous for his knowledge of league rules and loopholes, to the point that he became known as "Rule Book Roger." He once put a defenseman in goal for a penalty shot (goalies can't leave the net to bodycheck a shooter off the puck, but defensemen can), forced nearly continuous penalties to relieve pressure on his team (no matter how many penalties a team has, only two players of five can be in the penalty box), and had his goalies leave their sticks in the goalmouth when pulled for an extra attacker, to block attempted empty-net goals. There are rules against all of these now. The current rule is that taking a Too Many Men On The Ice penalty, or other penalties intended to disrupt the flow of play, in the last two minutes of regulation or at any point in overtime while two men down results in a penalty shot instead of a minor penalty.
Timothy Ferriss, in his book The Four Hour Work Week, tells a story about how he won a kickboxing championship using a method that he described as Loophole Abuse. The rules said that a player who leaves the ring automatically loses, and the competitors weigh in one day before they actually have to fight. So he dehydrated himself (with the help of a doctor) to temporarily "lose" a significant amount of weight during the day before the weigh-in and regain it, and then proceeded to shove all of his less massive opponents out of the ring.
He has also described his method for relatively safely losing a lot of weight by dehydration and pointed out that this loophole abuse is very common, as are terrible accidents. Tim has called for weigh-ins to occur on the same day as the competition to prevent this and this stunt has highlighted this issue.
The longest game in professional baseball history, a 33-inning marathon between the AAA Pawtucket Red Sox and Rochester Red Wings, only occurred because of this. When the game began to run into the early morning, the coaches attempted to invoke the rule that stated an inning could not begin after 12:50 AM. However, the rule had accidentally been omitted from that year's rulebook, and the umpire insisted on going by the rulebook. The game kept going... and going... and going....
Another minor league example comes courtesy of former catcher Dave Bresnahan. He knew the rules did not permit a second ball to be brought on the field, but didn't say anything about other items. Naturally, he carved a potato into the shape of the ball and hid that in his mitt; with a runner on third, he threw the potato into left field, decoying the runner into running home, where Bresnahan tagged him with the real ball. Averted, however: the umpire nullified the out, declared the run valid, and ejected him from the game. Bresnahan was later released, but he got the last laugh, as the team held a day in his honor and retired his number.
The 24 Hours of Le Mans has a rule that tires cannot be heatednote hotter racing tires have better grip in the garages. However, they said nothing about heating tires behind the garages.
The GT1 class in the 90s required competition cars to be usable by the public, but not necessarily be sold to them. Every manufacturer in GT1 class in the 90s abused loopholes by creating homologation specials. These were all patched by 1999. Notable examples include:
Dauer built the 962 Le Mans as a exclusive road-legal supercar based on the original Group C car. Porsche saw an opportunity to enter it as a GT racer after noticing the rules does not specify how much cars need to be built. So both teamed up, and won the 1994 running of 24 Hours of Le Mans. ACO patched the loophole, but it did not stop homologation specials from appearing...
Porsche tried to create another homologation special machine two years later, this time at its own. Although regular 911s have been raced in Le Mans (albeit in lower classes) Porsche decided to create a new car, the 911 GT1, using the engine of the now-retired 962 Group C racer (which was the basis of the Dauer 962 above). The new regulations require only 25 road-legal cars to be built, so Porsche built those, albeit with detuned engines for emission-related reasons. One of them now rests in Porsche's museum.
The FIA GT1 winning Mercedes-Benz CLK-GTR also exploited loopholes. Mercedes built one homologation car in 1997 and kept it, while they created more cars between 1998 and 1999. The latter were sold to the public, however. The luggage space was made available by placing a small cubby hole into an unused area of the car's rear bodywork, although it would mean the luggage would be harder to access.
Nissan teamed up with Tom Walkinshaw Racing (TWR) to built the R390 GT1. Only two cars were built, one of them sold in an auction. The loopholes used are largely similar to the opposition, but Nissan had to increase the luggage space for the 1998 long-tail version to satisfy the ACO as the previous one was deemed too small.
When creating the GT-One, in 1998, Toyota designed the car without a luggage space, unlike other homologation specials, so they successfully convinced the ACO, that the fuel tank, when empty, would be able to hold a suitcase, and built just two road-legal cars (one of them now displayed at a museum in Japan and the other in Toyota's motorsport facility in Germany), rather than twenties of them, as Toyota realized that those cars was enough (which Nissan also did). Averted the next year as the GT-One ran as a LMGTP (with the GT1 class cancelled for 1999), without changes from the 1998 GT model.
Another football example, this time off-field. During the early days of the NFL salary cap, the San Francisco 49ers and Dallas Cowboys (considered the top two NFL teams for most of the 1990s) perhaps more than any of the others, engaged rapidly in this.
In 1994, the 49ers - having been denied trips to the previous two SuperBowls by Dallas, began grabbing defensive players left and right such as Ken Norton Jr. (signed from the Cowboys); Rickey Jackson; Richard Dent and Deion Sanders. Jackson (according to one graphic shown in the NFC Championship game that season — again vs. Dallas) was reportedly paid around $130,000 (league minimum then) but was getting much higher bonuses depending on personal performance and how far the team advanced in the postseason (the NFC Title win would net an additional $850,000). The 49ers won the Super Bowl that year, though some would complain that they "bought" that title.
Not to be outdone, Dallas decided to one-up the 49ers; snagging Deion away from that team the next year to a contract where he would be signed to a minimum salary while getting a $13 million signing bonus. The Cowboys won that Super Bowl, but the NFL quickly put a stop to it by enacting what became known as the Deion Sanders rule; outlawing such tactics by correlating a player's signing bonus with the yearly salary on their contract.
Both teams (and others) exploited side-contracts with advertising firms. If Player A signs with Team B, Team B will pay Advertiser C a sum of money. Advertiser C then turns around and hires Player A to promote their product, using the money Team B just paid them, circumventing the salary cap.
Prior to 1979 there was no rule in the NBA against drafting a player before he was ready to sign—thus allowing the Boston Celtics to draft Larry Bird in 1978 even though Bird would play another year for Indiana State. In fact, there was a specific provision allowing it (the "junior conversion rule", intended for players suffering financial hardship) but Bird was able to skirt the financial means requirement because he'd already been out of high school 4 years (he skipped his first year of NCAA eligibility when he dropped out of IU). The NBA named the Bird Conversion Rule, prohibiting the practice, in Bird's honor in 1979.
In Cricket, the rules state that if the ball hits the stumps but does not dislodge the bails, the batsman is not out. During the 80s, the Australian team played a tour match in India on April Fools' Day. in which they superglued the bails on, and then just stood back and let the ball hit the stumps.
As mentioned on QI, Thomas White showed up to a cricket match in 1771 with a bat wider than the wicket. At the time, there was no rule on how wide the bat could be; it was added in response to the incident.
Also mentioned on QI was a 1951 baseball incident in which the St. Louis Browns brought in a batter who was 3'7" tall and crouched, making the strike zone 1 1/2 inches tall.
That incident was one of Browns owner Bill Veeck's many outlandish stunts. The Browns were known as the most consistently worst team in the league, and rather than attempt to create a better team (probably impossible) he instead tried to boost attendance with theatrics. The batter's name was Eddie Gaedel, and his one plate appearance (he walked, obviously) was Loophole Abuse combined with Refuge in Audacity. His contract was filed on a Friday because Veeck knew once reviewed the commissions office would reject it right away, but filing on a Friday would delay that until Monday and give Gaedel time to appear in a Saturday game. His name was quietly inserted into the roster with no announcement of any change. (One attentive sports writer did notice the change in roster, but was ignored by management when he questioned it.) His number was listed as "18," but his actual uniform appeared as "1/8". When he was finally inserted as a pinch hitter, the umpire tried to block Gaedel's appearance; however, Veeck had the foresight to prepare for this by having Gaedel's physical contract on-hand, leaving the umpire no choice but to accept him. Gaedel stood at the plate with a toy bat (there are regulations in Major League Baseball about how large the bat can be, but not how small) and took four pitches (Gaedel had strict orders not to dare attempt to actually swing at the ball) and walked to first base to the applause of the crowd. He was then immediately substituted with a pinch runner. The walk did not affect the game's outcome and the Browns still lost to the Detroit Tigers 6-2. The next day, Gaedel's contract was voided "in the interests of baseball," and a new regulation was put in place that new players could not be inserted into a team roster before their contracts were reviewed, effectively keeping anything like Veeck's stunt from happening ever again. Although it was said Gaedel's official statistics would be removed from all baseball records, that promise was not kept. Eddie Gaedel's appearance is still in the books, and he remains the shortest Major League Baseball player on record, with one plate appearance, and a perfect 1.000 on-base percentage.
This wasn't the only Veeck stunt that was Loophole Abuse plus Refuge in Audacity. Once he held "Grandstand Manager's Night" - ain't no rule saying you can't give fans giant "YES" and "NO" signs and have them make the team's decisions for the day ("New pitcher?" "Pinch hitter?"). The Browns won the game; the actual manager did not participate at all.
In Game 5 of the 1976 NBA Finals between the Phoenix Suns and Boston Celtics, the Suns found themselves one point down with one second left in double overtime, no timeouts remaining and possession of the ball under their defensive basket. Faced with the near-impossibility of sinking an 80-foot desperation shotnote Three-point field goals are not introduced until the 1979-1980 season, so even if they make it they would only got 2 points; and for that amount of range, you probably need to be Stephen Curry (who has an absolutely ridiculous three-pointer range), the Suns intentionally called a timeout the tean did not have. While this gave the Celtics a Technical Foul free throw, which they made, it also gave the Suns possession at halfcourt, and enabled Gar Heard to sink an 18-footer as time expired to force a third overtime. NBA rules were changed to award both a free throw AND possession the following year to prevent a repeat occurrence.
Muggle quidditch, one of the world's youngest team sports, has already gone through seven editions of its "official" rules, owing to the need to patch up innumerable loopholes as they emerge. For example, when coming into physical contact with one's opponent from behind was prohibited, savvy players started to initiate tackles by turning their backs on their targets as they charged them, in an attempt to get the opposing players fouled out.
"Three Point Stance" rule in Unified Rules of MMA forbids leg strikes to opponents head when he is touching the ground with more than just his feet. Initially it aimed to get rid of Kick Them While They're Down situation prevalent in PRIDE FC. Some fighters however intentionally drop a knee or a hand to the ground when they're held in a clinch to prevent opponent from kneeing their heads.
Before the 2014 WFTDA Championships, there was no rule in Roller Derby forbidding a skater from advancing when she wasn't on her skates, which Suzy Hotrod of Gotham Girls attempted to exploit during the championship bout with the Wheels of Justice (Rose City Rollers' All-Star team). However, she was called on a low block penalty when she touched the legs of her Rose City blocker trying to crawl between them. Ultimately pointless as Gotham Girls won the Hydra anyway.
In the 2015 season of the robot combat competition Battlebots, Complete Control easily disabled its opponent Ghost Raptor with a net concealed in a box wrapped like a present. Although entanglement devices like nets had been banned in all Battlebots competitions prior to this point, Complete Control's team asserted that this rule had been mistakenly left out of the 2015 rulebook. The referee stopped the match, disqualifying Complete Control for breaking the apparently non-existent rule, but the judges subsequently allowed the robots to compete in a rematch without the net.
Soccer/Football: There's no rule saying a player taking a penalty has to shoot. Most famously, Johan Cruyff took a penalty by unexpectedly passing the ball to teammate Jesper Olsen, who returned the pass for cruyff to score. Copied later by Robert Pires and Thierry Henry (badly and unsuccessfully) and Lionel Messi and Luis Suarez (successfully).
The rules say a player taking a free kick can touch the ball only once, and then can't touch it again until another player has. However, in 1970 Coventry's Willie Carr and Ernie Hunt noticed there was no specification of exactly what "one touch" meant..... The rules were changed by the next season.
In MotoGP, when the woefully underpowered Claiming Rule Teamsnote This is mostly because the CRT teams have to use production-spec engine, whereas the Factory class can use racing-spec engines were restructured into Open class in 2014, in hopes to for them to catch up with the Factory teamsnote Manufacturers and their satellite entries; two loophole abuses happened:
One, the rules for Open class simply requires the teams to use the standard ECU and identical software for all Open teams. This originally meant that the Open teams have to built their own bike, use a CRT bike with new ECU, or get a downgraded version of a Factory bike. However, no rule said that the Open teams can use full Factory bike with standard ECU's; in which no Open teams but Forward Racing realized. So, they decided that they would get rid of the CRT bike they have last season and get what is essentially a 2013 spec Yamaha YZR-M1 with standard ECU. This, combined with the riding abilities of their lead rider Aleix Espargaró, allowed Forward to crush the Open class competition; Aleix even got a podium and a pole on that season!
To see just how big Forward's advantage over the rest of the Open class in that season, Aleix finished seventh in the final standings with 126 points. The next Open bike is Scott Redding with a downgraded Honda Factory bike, in 12th place with just 81 points. There's a gap of 4 Factory bikes between Aleix and Scott. Aleix alone beat 6 Factory bikes!
Two, no rule explicitly said that a Factory team can jump to the Open class. This is what Ducati attempted to earn the benefits of being an Open class teamnote No engine freeze (thus more research and development), more engine & fuel allocation, and allows the use of soft tires. This caused MotoGP to create another class; the Factory 2, which is a Factory team with Open class benefits, intended only for Factory manufacturers who failed to score a win on dry conditions during the previous season or Factory manufacturers who are new entries. Those benefits are cancelled if they get enough number of podiums or a win on dry condition.
This rule, turns out helped to bring parity and closer competitions; so even after another restructuring in 2016 which sees the Open and Factory class being combined into one single class (due to the ECU's used by Open class are now used by everyone), this rule is still applied for all manufacturers.