I had a situation one time-Marriott Dulles I think-booked a weekend rate for a Thurs-Sat stay which included restaurant breakfast not lounge. They argued with me at check in that Thursday was not a weekend day and breakfast was not included. I had to pull up the reservation and show them. Hotels do tack on Thursday to weekend pricing. I've had that several times. I was really irritated about them giving me grief on a rate in their system.