If you use Facebook - as I do - Facebook in all likelihood has a unique digital file of your face, one that can be as accurate as a fingerprint and that can be used to identify you in a photo of a large crowd.
In my theater pieces, I would do "Tits on the Head" - Polaroid photos for $10 on the stage. There would be a line of folks paying me $10 for their turn. It was public prostitution. I turned my whole audience into johns. But because it was in a theater context, an art context, it was socially acceptable.