Josh, the complete contents of the oil tank will end up in the sump, I know from experience!
The problem arises from having a gear pump which has necessarily clearance between the gearset and the housing.
Oil will flow around the gears and should be stopped by the check valve in the crankcase behind the delivery port.
Over the years, the valve seat will have become pitted etc. and the spring will have lost tension therefore oil will leak past.
Another source of leaks is the pump body joints and possibly the mounting face.
The amount of oil in the scavenge pipe is negligible and if it leaks back it will not cause a wet sump.
So I guess the answer to the problem is to make sure the check valve is seating properly and has enough spring tension when the engine is pulled down. Otherwise, live with it or start the bike regularly.
Trev.