You can now limit athletes to one reservation per day in Kilo GMS, with separate settings for classes and appointments. When a limit is on, an athlete who already holds a spot that day can't reserve a second one, which keeps spots open for athletes who plan to attend and keeps your rosters accurate.
Turn the class limit and the appointment limit on independently in Settings → Gym Settings
Count waitlist spots toward the limit so athletes can't hold a waitlist and a reservation on the same day
Add athletes to a second class or appointment yourself whenever you need to, since staff are never limited
Both limits are off by default, and turning one on doesn't cancel any reservations athletes already hold.
For the full walkthrough, see Limit Athletes to One Reservation per Day.