Sounds to me like this is a weird one off situation. For a while, I never got around to removing a hacked/former credit card from my profile but always checked in with a valid card. With dozens -- well probably hundreds -- of stays, I never had a rate change like you describe so that seems unusual. Also. at check-in, the hotel normally confirms the rate so I don't know how this happened. Seems to me that it is a hotel problem. I've had hotels fail to take off internet, charge me for parking when I didn't have a car, and room charges that aren't mine. With 150 nights a year, that's something that happens occasionally and I ask the front desk to write it off. Doesn't seem like a system error -- just an occasional human flaw like when I tell the guy at the bar the room number for last nights Marriott rather than tonight.