I have heard that on the day of a boy’s upsherin, some hold that he is not allowed to see any women who are untzniusly dressed, so they put a tallis over him when he is outside. They also hold that he can’t touch any females besides his mother (and maybe other relatives as well). I found this out when my friend’s son had his upsherin. She had promised me that I could cut a lock, but it turned out that I wasn’t allowed to.
Maybe that is where this idea came from.