I’m guessing they could easily support this with a simple premise: Examine a legal fetish, which AI can generate images of, and ask people who generate those images if their consumption of real images have fallen as a result. Also check if actual real life participation in it has been reduced due to the ability to generate the scenarios privately.

It will be skewed if the fetish is legal, since participating won’t land you in jail. But there may be some out there that present other risks besides legal ones to help with that.