There's a Fridge Brilliance element to the Spiked Whackers when you realize they show up most (if not all) of the time right after the Rib Rage—the Brilliance part comes when you consider that the latest rib crossed before the contestant wipes out may determine the algorithm of the Whacker's movements. Although we have yet to see either a Rib Rage completely crossed (the distance between ribs coupled with the excessive padding on each rib essentially makes it impossible) or an occurrence of the Whackers both popping out fairly (or even not at all), it has not yet been confirmed that it's indeed impossible. (A beat.) Then again, if the Whackers are controlled by somebody with a lever, we're all screwed anyways.
The general design of Over and out, the first challenge of the Spring Wipeout Zone. Throughout the show, it is shown that simply running fast is never an effective strategy in dealing with obstacles. They assume that it is the same in this case, and hang on for dear life while they ride it around. But in this case, it is easier and faster just to run to the platform.
Same applies for the 2011 summer course with the maze obstacle. Simply, you have to enter a rotating maze (really, more like a circle cut into a bigger circle with some bumps) on yellow and exit on red. It hasn't yet occurred to people that since the entire thing is a spinning circuit, you don't have to run forward to get to red, you can simple crawl backwards. Though maybe that's in the rules.
It did seem to occur to the contestants of Episode 3, at least, who all used that tactic and had no problem getting to the exit. (Actually leaping from the exit to the opposite platform, on the other hand...)
Fridge Horror: This is a stunt show, so things may occasionally go wrong. Nothing does go wrong, but several times the show seems to have dodged a bullet. One episode had a girl who tumbles down the Big Balls and hits her head on the padding around the metal base ring, sliding of However, the padding wasn't there since the beginning: had this happened in the first episode, a broken neck may have ensued (a contestant did end up getting stuck between the ball and the metal ring, but somehow suffered no injury). Also, the change to the tipping floor motivator was because the pendulum seems to carry a high risk of whiplash (clip's from the British version, but still)
Though a more plausible theory: the tipping floor motivator is a lot more unexpected than the pendulum one.
Another 2011 Winter episode had an Action Girl make it all the way to the Wipeout Zone only to be forced to medically withdraw as well due to it being too dangerous for her (she had an old injury that was aggravated by the physicality). Note that one can see her receiving and nursing the injury through the second and third challenges but power through to qualify.