I've sometimes found a small portable refrigerator in my room that I suspect was used by a previous guest and not removed by the hotel. No problem, assuming that the hotel doesn't try to charge me for it, whether or not I actually use it. OTOH, this could be why hotels don't always have enough refrigerators available for the requests they receive.

I don't remember where, or even whether the property was a Starwood, but I recall seeing a sign in the room that for a fee, someone would empty the minibar so that it could be used to store the guest's own items. I didn't do it and I have no clue what the fee was, but it reminded me of the hotels that will restock one's minibar for a service fee. (I've never used that service either, but it sounds W-like since that brand seems to want to promote a party image and generally has minibars in rooms.)