Wrong. SS agents are generally not allowed to touch protectees unless there is a very serious reason, at least that’s what I read.
I just read Clint Hill’s book, Five Presidents, in which he chronicled his experiences protecting Eisenhower, Kennedy, Johnson, Nixon, and Ford (and some of their wives and family). He made this same point throughout the book: SS agents are forbidden to touch the people they are assigned to protect unless, for example, the latter extend a hand in greeting.