As I was checking out of the San Jose Fairmont hotel this morning, the Registrar asked me if I'd had taken some cashews and M&Ms from the mini-bar; I was shocked! Usually the front desk is clueless about mini-bar purchases. I had the cashews the day before, so someone could have known I'd taken those, but I'd literally grabbed the M&Ms just minutes before checking out; no-one could have known I'd taken them.
I asked him how he knew that, and it turns out the mini-bar in my room had weight sensors which detect when an item is removed from its place. Very cool!
Although I suspect it was expensive to deploy throughout the hotel, I'm pleased to see the stagnant hotel industry innovating. I'm constantly double charged when I buy something from the mini-bar because I tell the Registrar at checkout, then the maid indicates that an item was taken as they clean the room. The weight detection is a great solution to this problem; nice work Fairmont!