At Reed College, back in the day (late 80's/early 90's), we had "scroungers", who were a pack of people who hung around the dining hall, and would intercept plates of half-eaten food being brought by the paying diners to the clean-up window.

It was good etiquette, if you were such a paying diner, to inform the scroungers that you had a cold and that your leftovers were probably swimming in rhinovirus.

I was never a scrounger, nor associated with same...