I'm not sure you can really say there is "no teeth" when the RIAA is out there suing people for downloading mp3s.
The legal issue, if I remember a prior thread on this correctly, is that the act of copying is either fair use or not, and today's copyright law tends to measure whether or not its fair use at the time the act is committed. Thus, making a copy of a disk you own is probably fair use. Making a copy of a disk you do not own is not. There is also the first sale doctrine that permits you to sell a CD you have legally acquired. Put those together and you may "legally" have the right to copy a CD you own and sell the original. I happen to think that if a judge was called upon to decide whether you not a person copying a 1.5K collection of CDs and then selling the originals was engaged in "fair use," s/he might find the copying was *not* fair use.
Regardless of the pure legality or illegality of the act, however, seems to me that fairness to the artist dictates not keeping a copy if you sell the original.