Autoslash still uses a similar business model. They’ll keep checking rental rates right up until the day of your reservation, automatically canceling the old reservation and making a new one.

Haven’t used it in quite a while due to Covid, but it was pretty cool booking for $40/day, then seeing it go down to $35, then $27, then $22 and finally $19. All automatically.

How come the rental company doesn't wise up to his phone number or name? Are they that afraid of losing a customer that let them down a hundred times before?

I'd just tell him that there's no cars, or something.

It didn't matter to them because the reservation was just a row in their database and didn't prevent them from renting their cars to anybody else.

I am sure they have some ratio of cars to reservations they keep based on actual no show/cancelation statistics.

A reputation system could solve this. Do that a few times in a given time period and you become persona non grata.

Sure, but that’s just one possible way of implementing enforcement of reservations, which the first commenter claims is untenable because of competition.

The untenable part seems to be 'anticipation of sticker shock' though - a reputation system would affect chronic cancelers but (assuming your PR department is on its toes) quite possibly largely not be visible to incidental cancelers or people who're not actually going to cancel and are just scared of getting screwed.

It still might not work, but as implementation approaches go, the business risks seem substantially different at least.