A little voodoo?
In some magic-based religions, things like nail clippings, hair, and even dry skin flakes can be used in rituals to try and do harm to the individuals they came from. If you have someone’s toenail clippings then you might be able to hex them, or even case a love spell on them. Followers tend to keep a close eye on their own “off-cuts” for this reason.

This person giving themselves a little manicure on the runway before takeoff obviously hasn’t heard about this belief. They’re quite happy leaving clippings all over their seat and the one next to them. I’m a little baffled at how they got the clippers through security in the first place, though.