In response to Sydney's post..

Having worked in the photography industry (and been forced in front of a camera a few times in my day..) as a consultant and a make-up artist (10 years in that industry) I've written, signed, had others sign, and dealt with model release forms a million times over. Here is a nice standard break down of that from the NYIP:

http://www.nyip.com/ezine/techtips/model-release.html

If we require permission for use via OTRS, I don't know why we can't have "model release" be incorporated sexual/nude photography, modeling photography, studio photography. Materials used for educational purposes, as Commons is supposed to be, this shouldn't be too hard. I haven't thought too hard about it yet, but, it is possible.