This happened to me at the Mirage in Vegas. The mini bar person knocked and walked in at the same time, with no delay. Then she chastised me for putting a mini bottle of champagne in the fridge. I was unaware that the fridge was computerized and it was recording strange purchases. She was incredibly rude. I wrote a letter to the manager and received a lovely apology letter with the offer of 3 free nights! Needless to say I was shocked.