It would be very easy to do this in nearly any hotel that has no-click or simple click-through WiFi. A tiny box affixed to the back of the TV set, or someone opening up the clock radios that most Hotels still have and adding a camera and an ESP-32.

Hotels should look for devices that seem to stay on their wifi for a long time.

Of course, if it's profitable you can just use a cell modem and pay for the service and not be on the hotel WiFi

Someone capable of setting up tiny PCB camera will use data plan from a mobile network rather than a hotel WiFi.