no, that's the point of the bolt underneath, you empty it. The other pipe can be bunged up, but ideally it should be connected to the intake or perhaps back into the dumpvalve (for OEM Setups) as that will pull the air from the PCV Valve through, and actually drag the oil and muck into the oil Catch Can
98_Glanza - apart from look pretty, what an Oil Catch can does is it catchs the oily deposits and vents gases produced as byproducts of the combustion process, which are then expelled by the PCV Valve, and instead of plumbing it back into the intake - which creates a mixture which lessens the effectiveness of the incoming air, and leading to a higher probability of detonation - it catches said oil, and vents said gas