I'm curious what sort of POS machine they're using at check-out? My experience has always been that I provide my credit card at check-in when they do a pre-authorization. But, when I check-out, the hotel just charges my card for the balance on my account. Many hotels offer a 'fast check-out' where you just leave (or text them that you're leaving, or tap button in the app that you're leaving, etc.), but I don't recall using a traditional POS credit card terminal, like you would at retail, when checking out at a hotel. At least where I stay, I'm not using a POS machine where I could be prompted to leave a tip, even if they wanted to implement that. Is this common in some markets, to check-out using a standard retail POS terminal?