Lillie nails the real issue with permissions in SL.
(BTW: In RL, there's the Doctrine of First Sale. If I buy something and decide I don't want it any more, I can sell it to someone else, or give it away to the tenth caller or the first person I see walking down the street. Copyright doesn't preclude my doing that, as long as I haven't made any copies of the thing I'm selling or giving away.
SL could implement that--if copies are identified as such, they could all go along with the original. Why isn't that allowed in SL?)