Question about the upcoming VGC tournaments.

So, is it true that you're only allowed to use the pokemon you obtained from Pokemon X and Y and not the ones you will transfer via poketransporter/bank?

Also, if the latter is false, how will they be able to tell whether the past gen 5 and down was generated via pokegen? My friend said I shouldn't even bother breeding since everyone will generate using some cheat and make their pokemons legit.