Mil80c , another point you need to be
aware of;

Many gliders, e.g. mine (a Ka6E), have neither panel space for a
transponder nor capability of carrying any more weight for the extra
batteries - I am already on max AUW, on a CofA which has already been
extended as far as it can be - I am 208 pounds with a parachute, and
there are plenty of heavier pilots than that.

If a new generation of lightweight, low power transponders emerges (the
UK CAA has persuaded one manufacturer to build a prototype which tested
OK), and if ICAO accept 20 w output instead of 100+, and if the thing is
taken to commercial production, and if it can come with an option of a
small remote control panel I could strap to my knee, with the larger
piece and battery going into the stowage behind the pilot's seat, and if
I can lose enought weight to compensate for it, then it might be viable.

I'm not holding my breath while we wait for all that to happen.

Regards - Chris N.