Pondering a little further, I think it also makes a major difference if someone can *get away* from the touch easily. A tap on the shoulder is minimal contact and can be moved away from easily. An uninvited hug can't be, which is why one would normally be more careful to check consent before hugging someone than tapping them on the shoulder.
no subject
Date: 2012-10-17 07:56 pm (UTC)