Aria Hotel Minibar

My parents and I stayed at the new Aria Hotel in Las Vegas last week. Like most "luxury" hotels, they have a minibar in the room with ridiculous prices. Like many travelers, my parents brought some food and drinks, and used the minibar fridge to cool them.

I checked out without seeing the bill and today I noticed a lot of extra charges on my credit card. I called Aria and they sent me the invoices. For my parent's room, there was $35 of minibar charges:

Diet Coke $4.50
Water $5.00
Water $5.00
Coke $4.50
Sprite $4.50
Pistachio $12.00

I told the CSR that we didn't use any of the items. His response was that there are sensors in the fridge (and on the desktop evidently) that charges you if you remove an item for more than 30 seconds. He did remove the charges without me complaining further so my guess is that they get a lot of calls on this.

There are thousands of rooms in Aria. It must of cost a lot of money to put weight sensors on each minibar item in each room. Is this a good investment?