If I remember correctly, this has happened to me once at Marriott and debatably once at Hyatt - the Marriott experience (JW Panama) was bad as they wrote the wrong room number on the packet, then made me new keys for the wrong room because I couldn't get my key in the elevator to work for the wrong floor. The Hyatt experience (HR LAX) was debatable because I was checked into a room with all of the sheets messed up - not sure if the room was actually occupied or just had not been made up.