I was down in El Paso, TX for a family affair and one of my relatives had a reservation at a Days Inn. He had guaranteed it with a credit card and showed up around 6pm.

They gave away his room since he had not 'guaranteed late arrival'. I thought giving the credit card does guarantee that, but apparently not. Even with Marriott, they ask me what time I plan to arrive. I always say evening no matter what to get the 'guaranteed late arrival' on the reservation.