Legal does not mean "accepted". For us you could replace it with hugging: "Can I delay or prevent someone from getting from point A to point B by hugging them in the hallway? What if three people all decide they want to hug same person at once? Twelve people? A hundred?"

Most interaction between people is controlled by people losing social status when behaving wrong, and some mild violence (mostly pushing away) for more extreme misbehavior. Laws are only needed for really extreme cases.