"Placing cupped hand on shoulder of a stranger, with squeezing or stroking, with "friendly banter" = really not okay."

Nope, still not worth jail time. Move away from the person or grab their hand and remove it from your shoulder. I'm sorry, but you do not get to have people arrested for giving you an unwanted shoulder rub. If they persist, then yeah, they're assaulting (and harassing) you. Again, let's have some perspective.