Room number and check-in/out dates on the hotel keycard. What could possibly go wrong? How does stuff like this even get approved, esp when it comes with in an envelope with the very same information?

One of my pet peeves that I am nurturing a lot is asking hotel front desk agents to remake room keys ("I have a late checkout and my key hasn't been updated"). It's mindboggling how often I get new keys without being asked for any verification. I just received keys for TWO random rooms.