Zero tolerance policy - maybe I'm just too jaded, but I've never seen it used as anything but a tool to fire someone whom management already wanted fired.
Yeah - my company has a lot of "zero tolerance" policies.
One lady in our safety department had a beef with one of the guys in the warehouse. She whined until the head of the safety department decided that most of the warehouse was a hard hat zone. Zero tolerance policy. Except when they'd catch someone without a hard hat, they'd suspend him a little bit. Until they caught the one guy. He was let go.
Soon after, they decided it wasn't a hard hat zone, anymore.