[.LiT]

and I will be able to be on the network together with the guy I got the mac number from?
and it wont attract unwanted attention?

I'm not sure about that either. But you can kick the other users off with aircrack-ng program and then authenticate before the user you kicked off has a chance to.
(tip: use one wireless adapter for booting the other user off and another one to authenticate to the router.)