Yes, but through the tier rather than the booking.
If a tier has **Allow bookings over the allowance** turned off, any booking that would take the member past their monthly or yearly cap is blocked, for staff as well as customers. When staff hit it in the dashboard they get an extra hint that customers never see:
> Turn on "Allow bookings over the allowance" for this tier to override.
That's the override. Change the setting on the tier, make the booking, and change it back if you want the cap to stay strict.
There's deliberately no per-booking bypass. If there were, the cap wouldn't really be a cap.
See [[Booking Allowances]].