I've put a breather pipe on mine, but still, I imagine that moisture is collected by being sucked in as the whole heap cools down. Surely that must be what happens with the standard breather, rather than all the water just splashing directly in through the vent?
Is Redline meant to have properties to deal with this, for life?
Unless all your journeys are long and you're sure that moisture is getting boiled and vented out again, I'd be inclined to change oil, even if at an extended interval. It could be just an unreasonable 'motorbike thing' though. I don't cosset cars so much.
Nogbad can let us know how it goes after a good wet winter
and DL can report back after he throws in a cupful of sand to soak-up/filter out the water.