On ebay and in various web sites (e.g. www.vmspot.com), I see
compilations of music videos for sale.  These often state that the
videos are freely provided by the record companies or others for
"promotional purposes".  Being such, the sellers claim that they can
redistribute them, charging a fee only for the service of packaging
them up.  For example, one ebay auction provided the complete
compilation of Madonna's videos, which they state were all
downloadable without cost.

My question is whether such claims are legitimate.  For the answer, I
am looking for websites that deal specifically with the legitimacy of
distributing music videos.  I prefer web sites that provide
authoritative answers (I've
found plenty of sites that give opinions on both sides of the issue). 
I know that this is a copyright question and that there are plenty of
sites dealing with copyright.  I'm interested in those sites to the
degree that they deal with music videos.