Plain and simple from both sides the photographer and the model to protect themselves should use a model release in modeling. The moment the photographer takes a photo it is their intellectual property they only legally need a release to sell a product with it or a few other circumstances. As for the model especially in a no-pay trade shoot which a lot of model shoots are (collaborations), the model has no guarantee to get he/she's photos back without a release and a drawn-out legal battle don't put yourself in this quagmire most professional photographers do this automatically anyway!!!!!