I only think I've done...
Its an agreement i use when i feel we both have something to gain but in not need of many images, Good way of getting just a smaller selection of images and making the shoot worthwhile financially too
I guess using that theory if the photographer has a set idea in their head for a TF shoot and the model likes the idea but not enough to add to their folio but thinks the photographer is good enough to work with and was seeking a paid shoot could discuss splitting shoot into what both parts.
I probably shouldn't have used the term creative input the way I did. What I had in my mind was determining the scope of what's shot during a session. So if I say I want to shoot art nudes in the scottish highlands then clearly I'm going to need your modelling ability and best interpretation of my objectives in order to make the shoot worthwhile. However if you were to turn round and say that's fine but I want to shoot some editorial, or whatever, because I've got plenty of fancy nudes but no editorial in my port, then that's an extension of the scope of the shoot which to me is suggestive of TF - I'll shoot what you want if you'll shoot what I want (and if both objectives collide so much the better). That's what I had in mind but clearly didn't express it very well.