Quoted By:
You aren't allowed to use any pokemon non-Gen 6 pokemon in an upcoming tournament in Japan. This is pretty standard, happens with every new Gen.
Independent of this, Nintendo also claims to have a method of detecting and rejecting any hacked pokemon that people try to get onto Pokebank. They are keeping quite about what these checks are, least anyone find a way to circumvent them.
Some people are skeptical that Nintendo's measures will be rigorous enough to prevent well-made hackmons from slipping through.
