Bleh... well if you wanna be a stickler for rules then sure. Then again by even sharing the game with a friend he's doing something bad. I think things like this remind me of how people are against illegal stuff yet have no problem downloading music or videos.
Yeah its illegal but to what end? That's up for you to decide and honestly I'd go with the nocd just because of the fact you no longer need the cd in your drive. However if you're really against doing anything illegal then you already blew it pal! you screwed up! the feds are gonna get you and your friend too! you're gonna go to jail for a long time.