I cite discrimination based on reflexes and availability.
Fairest solution is the bookings are open for 24 hours (plus a week or whatever), and after that the slots are assigned randomly. Youre notified if you've got one, so easier to get another slot if your available.
If you win a slot, you're excluded from other contended slots.
Doesnt matter if you're fast, and distributes slots about even, based on availability
Tough luck if you can only make the fancy slots