good point about high wing aircraft but the closest i had were these two, one that flew underneath me at around 300 feet on finals and landed ahead!!! another was the islander who flew underneath us downwind without seeing us. wouldnt have mattered if we been wingless we wouldnt have seen them!
they used to use a technique called ' looking out before turning' when i was an instructor! even used to lift the wing up. in my experience high wing pilots were more aware of the need to lookout. remember the ba hamble students that descended on one another, thats why all ex hamble cherokee's have windows in the roof!