If they did this to me, I'd be calling the hotel chain and filing an offical complaint. I'd be up there shouting in the manager's face, doing all the operatic hand movements, you know, finger-to-chest foaming-at-the-mouth and everything, especially with what Canuck44's said about privacy laws.
"...Why in f**king hell should I be held accountable for a few f**king pieces of cardboard that merely say, "AMMUNTION?" Maybe I should give my family a cardboard box that says, "PRESENT" on it and expect them to dance around with joy. And here you go, blabbing about my personal information simply because I had a few pieces of cardboard left in my room - what, is cardboard too heavy for your maids to lift and put in the garbage?"
- Dave.