The longer version
A no-show is the worst outcome for a slot. The court sat empty, the player who wanted it was turned away, and unless payment was taken at booking the club was not paid either. It is different from a late cancellation, where at least the desk knew.
Clubs track no-shows as a rate: no-shows divided by bookings over a week or month. Free-to-book slots and pay-at-the-desk clubs see the highest rates. Card payment at booking and a clear no-show fee bring them down.
The usual mistakes are having no policy, or having one and not applying it. Mark no-shows at the desk so the pattern is visible per player, then decide: a warning first, then a fee, then a booking limit for repeat offenders.