You say that this is not what the thread is about.
We have a rule at our club that if there are any tee slots on the day of a comp not booked you can go in to the proshop and ask them to book you in to one of them.
My last club called it a start sheet, not a comp sheet, for the same reason. If there were spare slots on the day, and you didn’t want to play in the comp, you could still book the slot.