this is one of my pet peeves. if you're cutting across the trail you should be VERY aware of what is uphill. i understand its ultimately the person downhill who has the right of way, but the downhill person has the responsibility to look uphill before making erratic moves such as cutting across the entire trail. you wouldn't change change lanes without looking behind you...would you?
i didnt just cut across. i stopped on the side of teh run. looked across and up then began traversing. nobody was in the immediate vacinity for me to worry about.