I've had a transponder in my glider since 2006 and, like John, have the benefit of watching commercial airliners diverted around me. I also once saw a pair of F-16s pulling a high-g maneuver to avoid me. However, it doesn't confer immunity from all power traffic, especially light twins and some military aircraft. The nearest collision I've had was another glider flying head-on under a cloud street - we passed within 100-feet of each other.

I'm not sure the FAA always pays a lot of attention to glider traffic after I inadvertently flew into Mexico and back not too long ago - that usually brings Border Patrol aircraft on your tail! They either didn't notice or decided to ignore me!

Mike