Every now and then I have a guest who ignores the check-out time. Usually it's no more than 15-20 minutes, but one time it was an entire hour. (With that one, I'm pretty sure they thought check-out was noon, instead of 11am, awesome guests otherwise, and I didn't care because I didn't need to turn the room over that day anyway.)
Guests who don't check-out on time bother me a little because in my mind it's disrespectful, but at the same time, it feels petty to complain about overstaying by 15 minutes. And it usually doesn't affect my ability to get the room turned over.
If they were generally good guests, I don't mention it in the review or mark them down for staying 15 minutes after check-out. If they had other issues though, I usually add the late check-out issue to the list in the review.
How do you feel about late check-outs? Do you mark those guests down?