So I've heard Pokebank can tell when a Pokemon is fake?
Please tell me this is true!
This gets brought up a lot but basically whenever GF has a checking system for this stuff it's for really, really obviously modified 'mons.
The checking systems they've had in the past denied Pokemon with wrong abilities and impossible move sets, but modified Pokemon with correct move sets and abilities with two stats filled up in 252 EVs didn't get detected. Pokemon like that are considered legitimate, despite having not been legitimately caught or EV trained. The software (PokeSAV/PokeGEN) leave no specific traces on the Pokemon when made to indicate it wasn't caught in the game.
So basically, GF would need a really fucking good checking system in order to detect Pokemon that weren't legitimately trained/caught. And I just have very serious huge doubts they will. When it comes to GF checking for illegitimate 'mons, most people familiar with PokeSAV/PokeGEN know ways to workaround their checking systems... by making the Pokemon follow under GF's rules on what is considered a legitimate 'mon.
Basically, it will throw a alert up when it finds a Pokemon that knows something like Secret Sword but it won't go alert on something that is correct. This is all me assuming things, though, so I
could be wrong come release of the Bank. But GF's track record with this sort of thing is generally always the same.