Event Pokemon and PIDs

[Rabbit_2011]

Some guy is giving away Event Pokemon like MOVIE13 Celebi and GAMESTP Celebi via the GTS exploit. However, I think he has modified the IVs and Nature on some of them. Does that affect the legality of these event Pokemon?

I was thinking that all event Pokemon would have the same PID right, or are they randomized?

[Guest]

It doesn't affect the legitimacy of these event, since these are hacked anyway.