Mine has been catching a good bit of slimy sludge that ends up forming in the inlet hose and top of the filter housing. Probably a combination of oil/microbes and other growies/combustion byproducts, same stuff as ends up forming in the hoses if the oil gets that far.
Considering that you can plumb the drain hose back to the oil sump, and on bigger diesels this would make sense considering the amount of oil that would accumulate, it does make sense that you would design the filter to trap any sludge and other junk that you wouldn't want draining back into your engine.
I don't think plumbing it back to the sump on the CRD would be a good idea. Mine accumulates as much water as oil, due to condensation in the block when it's shut off, and then boils off thru the CCV when it's heated up again. While water vapor going thru the intake is no problem, draining liquid water back to the oil sump doesn't sound like too hot an idea.
I wouldn't be too concerned about the filter falling apart. If you check the pdf file on the Mann and Hummel website, this thing was designed to handle upwards of a 500 HP diesel and 200 liters/minute of air flow, and to last for a year in that application.
Second reason I'm not worried about it falling apart - as far as I can tell, Mann and Hummel doesn't have any affiliation with DC!
I'll keep mine installed for the time being, and see what oldnavy's design looks like. Would be nice to free up that space where the Provent is sitting for an engine coolant filter.