It may hurt in the sense that they say "We're not going to allow you to do that" (but note that the OP already has permission from someone, probably his manager and maybe even people higher in the picking order). But that hurts less than when they say "You shouldn't have done that, and now we're going to fire/sue you".

Of course, the OP shouldn't just talk to the legal department on his own, and certainly not with the opening "I'd like to do this". He should bring his manager (or whoever gave permission) with him.