FWIW I just reserved a room at the first Vegas hotel that Google served up (MGM Grand Las Vegas) and clicking through to the "Reservation Terms & Conditions" in

FWIW I just reserved a room at the first Vegas hotel that Google served up (MGM Grand Las Vegas) and clicking through to the "Reservation Terms & Conditions" includes: Room Status. MGM Grand reserves the right to check the status of all rooms/suites at any time. which sounds like it covers these sorts of inspections