For my recent stay at the Rome Marriott Grand Flora I pre-paid for the stay excluding the room tax. That tax came to 72 Euro, so I expected that charge when I checked my credit card activity, but I was surprised by a charge for about 9 Euro from the hotel on the same day.
I have no idea what it could be for. Breakfast was included in our rate and we didn't take anything from the mini-bar to my knowledge (I do have a 10 year old, so it's possible she got something, but it is highly unlikely.)
So would you just let it go or try to find out what it is for? I'm leaning toward letting it go as I pretty much hate calling anyone.