Consequences of catching Acreus and what is action replay?

Yea yea the only way is to hack it, but I wanted to know I just wanted to catch one for the hell of it. I heard Pokemon will ban you from Wi-Fi if they catch you hacking Pokemon, does that mean if you attept it youll be banned or if you use it youll be banned?

So here are my questions:

1) What the heck is action replay?

2) Is there serious consquences for hacking Acreus if you dont use him against your friends? (I alrdy have enough powerful Pokemon I dont need another)