This seems to be getting more and more widespread. As far as I'm concerned, it's a non-starter. I'd pay models before I'd sign a deal like this. I'd shoot a lot less, but this is a place where I will not go.
My first impulse is to say, "She's nuts," but it never hurts to ask, I guess, and all she's doing is making herself less attractive to photographers who aren't interested in this kind of deal. I've given (a) model something *sort* of like this - although she didn't have preapproval rights to my usage, she got pretty much unlimited use rights including some commercial rights with shared profits. But that model is, in her own particular niche, quite famous, and I was lucky to work with her, especially for free. It's all a question of relative contribution.