On Wednesday, December 4, 2013 10:22:42 PM UTC-5, Bob S wrote:
a rear view camera and display in their glider...

I think I should be too busy for a rear view camera to be more than a distraction, but there is a lot of research in the UAV community to use robotic vision for passive collision avoidance. Current research systems are very lightweight, compact and use very little power. If you eventually put one of those systems in your glider, it will be like having R2D2 in the backseat spotting boogies.