Data point for a California airport property (1 night stay): Booked a standard King, was automatically upgraded about a week out to a "premium King with sofabed" -- checked in on the app and chose the room.

Arrived at the property about 3 hours before check-in...since the digital key hasn't popped asked the front desk if there was the possibility of getting in early... Asked if I really needed the sofabed, I said no -- thinking I'd get booted back to the room type I booked. Instead thanked me for being a Diamond and pushed me up to the standard (US) Hampton Studio Suite which was most unexpected but appreciated.