I doubt it happens much in practice, but that seems open to abuse. I'd hate to be in a position where someone demanded my assets and I had to prove that I wasn'

I doubt it happens much in practice, but that seems open to abuse. I'd hate to be in a position where someone demanded my assets and I had to prove that I wasn't involved with them. Especially as it becomes ever easier to manufacture evidence like photos and video. Having both parties sign documentation ahead of time seems a little more secure and hopefully helps to keep things consensual.