Until your pads wear and the bladder in the reservoir allows the system to self adjust, leaving air above it that could possibly make its way into the rest of the open system if it's flipped upside down. Open doesn't mean it's just open to the elements in this case, but that it has a reservoir in the system.
Until your pads wear and the bladder in the reservoir allows the system to self adjust, leaving air above it that could possibly make its way into the rest of the open system if it's flipped upside down. Open doesn't mean it's just open to the elements in this case, but that it has a reservoir in the system.