That is not a very good approach for 2 main reasons.
1. Technical reason: the vacuum in the crankcase keeps down the oil consumption by preventing oil to leak through worn valve seals.
2. Ecological reason: venting oil fumes to the atmosphere is not a good thing for the environment.
yeah, I'm very well aware of this. unfortunately, I don't have much of a choice right now. The way it is all set up from the factory, running boost actually pressurizes the crankcase, which is bad for exactly the reasons you posted:any tiny internal oil leak will instantly be magnified. Once I find a good check valve, I will be hooking everything back up, with the catch can in the line.