I’d let them know. As someone else point out above, I’d be worried about selling it on and then Apple picking up on it when registered/connected online.
A few years ago I treated my mum to a stay over at a De Vere hotel not too far from us.
There were 4 of us dining on the Saturday night and this accounted for most of the cost of the weekend, the bill for food/booze ought to have been around £700.
After we’d eaten, we asked for coffee to be brought to a wee drawing room just off the restaurant. It was late, so we finished the last of the booze, drank our coffees and headed to bed.
I was sat at the check out desk the next morning with a sore head and they handed me my bill to look over. The meal from the night before was missing. I pointed this out and the girl joked that it’s not often guests highlight the stuff missing from their bill.
She went off to find my signed bill but was unable to locate it. I told her I didn’t remember actually signing anything and told her about moving from the restaurant to the drawing room etc just after the meal.
She said she would be unable to charge me for the meal without the bill and that it would therefore not be added to my final bill!
wtf!! I told them I was perfectly happy for them to put a new bill together, was told that wouldn’t be necessary and at which point I received an elbow from mrs file so we let the matter drop. I didn’t feel particularly happy when I left since I was concerned the very nice man who looked after us during dinner may get his backside kicked.