If the system were leaking refrigerant, wouldn't it rapidly stop working? It's supposed to be a closed loop. And it sounds as if it requires a fair bit of isobu

If the system were leaking refrigerant, wouldn't it rapidly stop working? It's supposed to be a closed loop. And it sounds as if it requires a fair bit of isobutane to cause problems, so if it's losing enough refrigerant to asphyxiate I'd think that it would soon stop refrigerating.