... Or at least they're likely to be [[MistakenForSpies mistaken for them]] whenever the era they travel to is familiar with the concept.

Think about it. If you're from a different time, then you:
* Possess a bunch of knowledge that most people wouldn't have, some of which may very well be classified in the time you've arrived in.
* Lack a bunch of knowledge about pop culture and current events that most people would have.
* [[LanguageDrift Probably have an accent that sounds slightly off.]]
* Can't convincingly account for your past, because you literally don't have one in that timeline.
* Have goals which probably look incomprehensible to other people, and therefore are likely to be taken as cover for something more sinister.

All of these will make you appear to be a spy to anyone who takes enough of an interest in you to notice.

Compare FishOutOfTemporalWater, the root cause of this trope.
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!!Examples

[[foldercontrol]]

[[folder:Comic Books]]
* This happens to JimmyOlsen in a SilverAge story when he gets transported back to WorldWarTwo and has to pose as a Nazi.
* The ECComics story "...For Us the Living" (''Weird Fantasy'' #20) begins with an atomic scientist being arrested as a spy for a foreign power. The scientist admits his identifying documents are all forged because he came from an alternate time-branch in which Abraham Lincoln escaped assassination and brought peace to the world.
* Mortimer experiences this twice in the ComicBook/BlakeAndMortimer album ''The Time Trap'', the first when he automatically says he's English... in medieval France. In the second, he's flung into the dystopian future and is found by rebels.
* In an ArchieComics comic, Jughead accidentally travels back in time to the AmericanCivilWar and is mistaken for a Confederate spy (one of the suggestions being that the S on his shirt stands for "Spy" or "South").
[[/folder]]

[[folder:Films -- Live Action]]
* In ''Film/HotTubTimeMachine'', Blaine and the ski patrol mistake the main characters for Soviet spies after finding their cell phones and [=MP3=] players (which they think are [[ShoePhone spy gadgets]]), and their can of Chernobyl energy drink with its [[TheBackwardsR Cyrillic lettering]] (which they think is a bomb).
* Chekov and Uhura in ''Film/StarTrekIVTheVoyageHome'', in the famous "Nu-cle-ar wessels" sequence. [[RuleOfFunny Somehow]] they don't realize that, if you want to get aboard an aircraft carrier in 1986, the guy with the prominent Russian accent ''probably'' shouldn't be your spokesperson. This doesn't cause them any problems in the end except for a bunch of strange looks, but when the inevitable transporter malfunction strands Chekov next to the reactor of aforementioned nuclear wessel he is assumed to be a Russian spy. His recitation of Name, (Starfleet) Rank, and Number do nothing to dispel this.
** One of his interogators ''does'' express some doubts, noting that while Chekov obviously is a Russkie, he's also "a retard or something" (that may be partly because he makes references to being a member of Starfleet and having a phaser).
* Played with in TheFilmOfTheBook ''Film/{{Timeline}}'', where a group of 1999 History students travel to HundredYearsWar France and are captured by English soldiers. A BloodKnight singles out the only French student, who the rest insist is their interpreter in order to protect him (the group is posing as English pilgrims). Claiming that he is going to test if this is true, the knight orders the student to translate aloud a series of sentences that the knight says in French, into English; if the student refuses, the knight warns, he will be proven to be a spy and executed immediately. [[spoiler: The last sentence the knight says is ''[[MortonsFork I am a spy]]''. When the student painfully complies, the other English soldiers take it as a [[DeliberateValuesDissonance valid confession]] and kill him.]] This is then [[spoiler: [[SubvertedTrope subverted]] when it is discovered that the knight is a time traveler himself and he knew from the beginning [[ForTheEvulz who the "pilgrims" were]].]]
** It doesn't help that one of them is Scottish (played by GerardButler), and England was at the time also at war with the Scots. The BigBad assumes that the Scots must be trying to ally with the French.
* In ''Film/SafetyNotGuaranteed'', this is happened for different reason: Kennetch is chased because ''he breaks into nuclear facilities'', for purpose to get ''something'' for his time machine.
[[/folder]]

[[folder:Literature]]
* In ''JohnnyAndTheBomb'', both Bigmac and Wobbler are mistaken for spies when the main characters travel back in time to the Second World War. As in some other examples, the WW2 people regard their modern technology as spy gadgets, especially a pocket radio. It doesn't help that it says "Made in Japan".
** Probably didn't help that Bigmac was wearing a german uniform at the time either.
* A frequent plot device in HarryTurtledove's ''Crosstime Traffic'' young-adult series. While not exactly time travel, the protagonists travel to alternate universes where historical events have departed from their own FutureHistory. In most of the stories so far, they get mistaken for spies. For example:
** In ''The Disunited States of America'' the protagonist [[spoiler: is travelling with forged identity documents in a war zone and steals a uniform in order to infiltrate a military unit--any of which would get him executed for espionage had he been caught, even though that wasn't his intent.]]
** In ''Curious Notions'' the protagonists [[spoiler: are suspected of being double agents by both the Imperial German occupation government and the Triads in San Francisco due to the actions of their predecessors (selling slightly more advanced technology from the home timeline to the locals--against company rules precisely because it attracts undue attention from the authorities).]]
** In ''The Gladiator'' the Crosstime Traffic organization [[spoiler: ''is'' actually participating in espionage, attempting to subvert the victorious Communist government by reintroducing capitalist concepts to the population in a timeline where the USSR won the Cold War]].
* The end of Creator/RobertAHeinlein's ''Literature/TimeEnoughForLove'' involves the protagonist travelling back to the time of his own childhood and dealing with the difficulties thereby. Despite being a 2000+ year old pansexual incestual time traveler speaking what, after 2000+ years, might as well be a foreign language in a ''very'' alien culture, he encounters no problems. However, his plan to escape having to fight in WWI is to hustle pool and flee to Brazil. He then realizes that that might get him killed by German or French agents as a spy.
* The Literature/TimeScout series doesn't say you'll be caught as a spy, but the results are the same. Get caught, get killed. Usually for [[http://en.wikipedia.org/wiki/Apostasy apostasy]] or some such.
* Played straight in the novel ''Timeline'' that the film mentioned above was loosely based on. An English knight suspects of a shy "Irish" squire (in reality an American student from 1999) being a French spy and challenges him to a joust to prove that he is not.[[note]]The Medieval assumption was that God would never let the right party lose a fight, regardless of the duelist training.[[/note]]
* Pops up a few times in the ''[[Literature/TimeMachineSeries Time Machine]]'' gamebook series, such as being taken for a Mexican spy during the Mexican-American war.
* In the third novel of the ''TheMilkweedTriptych'', Raybould Marsh barely escapes the EndOfTheWorldAsWeKnowIt by [[SetRightWhatOnceWentWrong traveling back in time]] to WorldWarTwo. Just before he time-jumps, his friend hurriedly gives him his billfold so he'll have some ready cash. Unfortunately the money and identity cards are all from 1963, so he's quickly detained by the police on suspicion of being a German spy with badly-forged documents. This turns out to be an advantage through, as the authorities release him the next day in a TrickAndFollowPloy. As Marsh ''is'' an intelligence agent, but a British one, he's able to escape their surveillance.
* A very common plot in modern Russian alternate history fiction is "modern guy falls into WWII". The first thing that happens to the protagonist is always capture by the NKVD because of this trope, or an attempt of such. How does the protagonist convince the StateSec that he means no harm (or dodge them altogether) is the first plot twist in such stories.
* {{Literature/Outlander}} has this as a huge problem for protagonist Claire in the first and second books, especially as she arrives in Scotland during the Jacobite period.

[[/folder]]

[[folder:Live Action TV]]
* In the ''{{Eureka}}'' episode "Founder's Day", a bunch of characters from the present day appear at an army camp in 1947; the general in charge of the camp spends most of the episode chasing them around assuming they're spies.
* In ''Series/StargateSG1'', the team finds themselves at the bottom of a missile silo in 1969, [[JustifiedTrope leading naturally]] to this assumption. It doesn't help that the officer who just spotted them [[BluffTheImpostor asks them, in Russian]], "Are you Russian spies?" and [[CunningLinguist Daniel]] promptly replies, "Nyet." O'Neill is not happy.
* This happens to Gary in an early episode of ''GoodnightSweetheart''. [[note]]Knowing Himmler and Goebbels' hair colour is what did it; his claims to have seen it in a newsreel fall a bit flat because Newsreels were monochrome.[[/note]] He decides to play it up and manages to convince his captors he ''is'' a spy, but a British one and not a German one as they'd assumed.
* ''Series/StarTrekTheOriginalSeries'':
** "[[http://memory-alpha.org/wiki/Tomorrow_Is_Yesterday Tomorrow Is Yesterday]]". When the ''Enterprise'' accidentally travels back in time to Earth in 1969, Captain Kirk is considered a spy when he's caught infiltrating a U.S. Air Force base. (When an interrogator threatens to lock him up for two hundred years, Kirk ruefully acknowledges, "[[TheSlowPath That ought to be just about right.]]")
** "[[http://memory-alpha.org/wiki/Assignment_Earth Assignment: Earth]]". When the ''Enterprise'' is deliberately sent back in time to Earth in 1968, Kirk and Spock are arrested as spies when they're caught inside [=McKinley=] Rocket Base.
%% Please see the discussion page before saying anything about Doctor Who.
* The Doctor and his companions in ''Series/DoctorWho'' sometimes fall prey to this, such as when they go to Skaro in "Genesis of the Daleks," where they are mistaken for the Kaleds' deadly enemy the Thals (or their common enemies, the wild mutants that run around in the nuclear wasteland). Everyone being HumanAliens in this case did not help. Sometimes the Doctor genuinely ''is'' a spy, working for himself, simply by virtue of being too nosy for the villain-of-the-week. Other times, such as in "The Brain of Morbius," the irate locals correctly identify him as a Time Lord but automatically assume he's there to steal their stuff because they're suspicious of Time Lords in general. The titular Morbius similarly assumes the Doc is there on behalf of the Time Lords to hunt him down and was just stumbling into the creepy castle as a ruse.
** In "Cold War", the Doctor and Clara end up on a Soviet nuclear sub. Naturally, the crew assumes they're Western spies, despite the TARDIS turning their speech into flawless Russian. This leads to an exchange where Clara says she's not speaking Russian... [[TranslatorMicrobes in Russian]].
* This is the premise of the ''Series/{{K9}}'' episode "The Cambridge Spy": a [[LightningCanDoAnything lightning strike]] sends Jorjie back to Cambridge in 1963, she's arrested as a Russian spy, and K9 and Starkey have to travel back to rescue her.
* PlayedForLaughs in an episode of ''BoyMeetsWorld'', in which an accident involving a microwave oven sends Cory back in time to a warped version of TheFifties. (It's AllJustADream.) Notably, they don't get suspicious for any of the reasons listed above, but because he doesn't buy into [=McCarthyist=] paranoia and isn't deathly afraid of a Soviet invasion like everyone else in town.
** He also has knowledge he shouldn't have, such as exactly what Sputnik is (i.e. a harmless metal ball with legs instead of a KillSat).
* Happens multiple times in ''Series/TheTimeTunnel''.
[[/folder]]

[[folder:Tabletop Games]]
* In the ''GURPS'' TableTopGame/InfiniteWorlds setting, this trope is played with due to the fact that Infinity Patrol agents routinely do become spies in the Alternate timelines they infiltrate, both to avoid the notice of the locals, as well as to hide from agents of rival Crossworld travelers from the Centrum timeline.
[[/folder]]

[[folder:Video Games]]
* In ''VideoGame/BackToTheFuture: The Game'', Edna Strickland is convinced that Marty is a spy named [[ImMrFuturePopCultureReference Yako Smirnoff]] (partially because a different time traveller told her this.) Additionally, Arthur [=McFly=] is convinced that Marty is an FBI agent.
[[/folder]]

[[folder:Webcomics]]
* Ophelia (a modern-day office worker) gets mistaken for a spy in [[http://www.irregularwebcomic.net/2958.html this strip]] of ''IrregularWebcomic'', because she knows that the Nazis never planned to steal the British Crown Jewels.
[[/folder]]

[[folder:Real Life]]
* The claims made by [[http://en.wikipedia.org/wiki/John_Titor John Titor]] fall into this category. He might be just another Usenet crank, a very skilled practical joker, or the real thing.
** Given that pretty much all his predictions failed to come true, and him failing to predict things like, you know, [[TheWarOnTerror 9/11]], it's almost certainly either of the first two. [[TakeAThirdOption Or both]].
* Recently, a mysterious figure in a Creator/CharlieChaplin film [[http://abcnews.go.com/Technology/time-traveler-1928-charlie-chaplin-film/story?id=11992878 raised eyebrows]].
[[/folder]]

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