Trust doesn't really work like that in practice though, photos are still typically assumed to be genuine to say nothing of the context in which they're presente

Trust doesn't really work like that in practice though, photos are still typically assumed to be genuine to say nothing of the context in which they're presented. The war in UA has a host of examples, genuine videos and images presented with various (made up) contexts to show anything the poster wants them to show. Add in modification (cropping, video cuts, as well as photoshop) and it gets even more complicated. Unless deepfaked porn is trivial to make by anyone, easily shared, wildly popular, and almost always perfect, I really don't think that "it's a deepfake" will work as an excuse. And that assumes that you'd be able to reach people to tell them that.