How the door PIN works
It is tied to your hour, not to you
Your code starts working 15 minutes before your booking and stops 15 minutes after it ends. Outside that window the keypad simply refuses it, so a code that leaks after the fact is worth nothing.
It is created late on purpose
The PIN appears about 2 hours before you arrive. Booking a week ahead does not put a live code on a door for a week, and it means cancelling early really does cancel the access.
The door can work with no internet
The lock checks the code against its own clock. If the club's WiFi is down, or the lock has no gateway at all, your booking still opens the door. That is the point of a time-based code rather than a remote unlock button.
Every entry is recorded
Each use is logged against your booking reference, which is how the club settles a dispute about who was in which bay without cameras in the room.