I believe that the SSA has taken the correct position on the ANPRM. The cost benefit to equip cannot justify the benefit of avoiding mid air collisions with gliders AT THIS TIME. My comment to the SSA was this:

"If the FAA cannot assure collision avoidance, via positive ATC, for all aircraft that are equipped with a transponder or ADS-B then the safety benefit, if any, of mandating use of the technology is marginal and the cost to the gliding community of implementing this change is not justified."

However, my personal opinion is that at some point, gliders, UAVs, and all other aircraft will have to equip ( ground to infinity) to provide some kind of "Electronic VFR" for separation and collision advisories or avoidance. Right now there is just too much uncertainty with a chaos of operational and proposed systems(Mode A, Mode S, ADS-B, TABs, etc). Google and the UAV community are working on low power/cost transponder that may do the job. I feel that all pilots should take some responsibility for replacing eyeballs with some kind of electronic advisory/resolution. That inexpensive technology is not there yet for most aviation (except for glider to glider with FLARM).

So... the best strategy is to wait for things to evolve before the 2020 mandate. It looks like incorporating UAV into the NAS system will be the driver for low cost transponders that may be appropriate for gliders.

Walt Rogers WX