I fitted a catch can to my Volvo a couple of months ago. Anyone who has a turbo a few years old, petrol or diesel, will have seen the oil around the turbo intake, leaking out around the hose. I fitted this catch can to my Pajero many years ago, just to see how much oil was actually going through the turbo...not much it turned out.
The Volvo already has a factory catch tank, my PCV system is working, but there is oil at the turbo inlet, and creamy goop at the PCV inlet to the hose. Very few miles over lockdown, and it was all close to home, but back at work for 7 days now, and checked the tank - it was nearly full ! 99% water with a very small amount of cream, so hardly any oil at all. I don't know if I want to drain water from this tank every week....and what if I forget ?
I think I've reproven what I proved 15 years ago - it's mostly water that condenses, so not a problem. The Volvo system works well at recycling the oil vapour back to the sump, and passing the H2O to the intake. It comes off tomorrow.