It says you only have to do it once, but I'm guessing that's once per computer. I wouldn't think there's any way the disc itself can "remember" that.
Confirmed - you have to enter the username/password once on every computer you put it in, AND you have to be an active, paying club member.
Hope all those sellers on eBay are telling bidders who are non-members that they'll only be able to listen to the audio CD. Actually, none of the seven I just checked now mention a thing about that.
So, buyer beware.