While many mechanics can be stolen (Ball lightning, for an example: gatherer.wizards.com/pages/card/Details.aspx?multiverseid=191393 and even Silence) it is not okay just to argue (IMO) that "MTG has this; Why don't we?" because if not, our card list shall explode.
If done well, stealing mechanics is fine; if not, it's a wholesale ripoff.
Copying card mechanics is a very risky thing to do.