What does it mean when you are finding safety pins?

Answer 1

This is the question of the moment for me. I work at a school and have been finding open safety pins surprisingly often on campus. Usually, not always, in the same area; smaller pins; not dirty or old; sometimes with a little bend mid-point of the pin side (opposite the catch side).

Anyone know anything about this phenomenon?

I noticed such a couple times on other campuses.