Nobody care ga! There is no security in the carpark. It's just like those carparks outside the normal public parks in HongKOng.
Last time I just ask the door boy in the hotel entrance & he said it is free. I asked even if I do not go to the restaurant? He said it is OK. I just walked around the hotel, take some photos and get back the car later. There is nobody in the carpark at all.
Those staying in the hotel will also park the car there. In that case it will even be for two days.