I agree with that too. Somebody who leaves a car parked in a SC spot long past when it's charged should not be doing that. Tesla should be able to tell when that happens without intervention. There might be extreme cases, such as a person plugging in at 2AM when all spots are empty, getting a few hours' sleep at a nearby motel, and hitting the road before there's anything close to a wait, but in general there's no justification for leaving a car parked when you don't expect to get back when it's done. Even if you are the only one there when you arrive, and are the only one there when you get back, it doesn't mean you were the only one there while your car was parked.
To be fair, I've never heard of a SpC being completely full between 11 PM - 7 AM (which is when most folks would leave their car overnight). I agree though that Tesla needs to crack down on folks who drop their car off at 12 noon and drive off in another car and don't return for a couple hours.