public function getRemainingCapacity($excludeId = null) {
		if (!$this->Capacity){
			return true;
		}
		$bookings = $this->Registrations()->filter("Status:not", "Canceled");
		if ($excludeId) {
			$bookings = $bookings->filter("ID:not", $excludeId);
		}
		$taken = $bookings->sum("Quantity");
		if($this->Capacity >= $taken){
			return $this->Capacity - $taken;
		}

		return false;
	}