It's a flight safety issue. If you guys want to operate gliders above FL100, where you ARE a hazard, then you must carry the appropriate kit.
Spitoon, you're quite correct, the RAF Tucanos have recently been fitted with a nice little TCAS system to enhance flight safety in the very busy Vale of York area.
It's not long ago that I came across a glider well above FL100 over Scotland in Uncontrolled Airspace, no transponder therefore no TCAS warning, not seen on radar...no warning...wasn't a close one, but, could easily have been.
What price safety?