That is true--I guess my point was, the 'First sale' doctrine that applies to music and video does NOT apply to software with a EULA (end user license agreement) you agree to. If they do not allow your transfer of the software, you can get sued for transferring the software. The difference lies in accepting a EULA, vs. a CD, tape, record, etc. that has no associated agreement. I believe there was a case involving Autodesk where they defended their right to 'tiered' distribution through the EULA.
Might be changing with digital video and audio. You could have a EULA in order to access digital downloads, they could stipulate whatever they want--i.e. we can delete your files remotely because of all those pages of crap you didn't read when you installed/opened the package.