The purpose of evacuating crankcase gases is more than just to maintain the breather tract clean, the reciprocating movement of the pistons on each revolution inevitably produces pressure, in short a build up of pressure behind the piston rings will increase the resistance to piston's movement and will not help the sealing of the piston rings.
You will only occasionally get pressure going to your catch tank from your tip and whether or not you can feel it is another thing but it's there and kind of defies the point of taking the preventative measure of fitting a well designed catch tank in the first place.
