It gets better than that. Once, I've seen / caught in the act / one ads-distributee who damaged the sticker on my box' lid. He was scratching it with a key. Then, suddenly vanished after seeing me.
After that, I got ads put into my box again. Once I asked one distributee if he can't see the sticker.. "it's damaged. So I thought you wanted to remove that, but it made problems so yo left it striken through"