I guess I would just laugh pretty hard to see the German police putting rules up to peoples nostrils one after another, because I'm not in Germany.

Only as a nitpick, they don't look like folding rulers to me, they seem like normal (non-folding) rod/staff of the kind often used in topography.

It would be dangerous to point one of those at someone's nose, a wrong movement or an accidental push and an eye could be seriously harmed.