Had a guy like that in high school - if you set anything down on the lunch table for an instant - candy bar, stick of gum, whatever - he'd snatch it.
One day he grabbed my box of Chiclets and
poured the whole thing in his mouth. Thing is, it was Feen-A-Mint laxative chewing gum.
He was only out for one day . . . but it cured him of stealing other people's snacks.
My Dad once told me that lunches were disappearing where he worked . . . until one day a woman screamed when she bit into a habanero sandwich that wasn't hers.
I've
heard of people doing things that are
considerably more harmful to the lunch bandits . . . but, fortunately, never at a place where I went to school or work.