https://www.federalregister.gov/documents/2016/12/23/2016-30910/transponder-requirement-for-gliders-withdrawal

https://www.facebook.com/ushpafreeflight/posts/1506592226020915

While most of us were holiday shopping last month, the FAA
withdrew a proposed rule to require gliders to carry transponders. This is good
news for free flight pilots, since there are currently no appropriate
transponders for us to carry.

The FAA is withdrawing a previously published advance notice of proposed
rulemaking that sought public comment from interested persons involving glider
operations in the National Airspace System. The action responded to
recommendations from members of Congress and the National Transportation Safety
Board and was intended to gather information to determine whether the current
glider exception from transponder equipage and use provides the appropriate
level of safety in the National Airspace System. The FAA is withdrawing that
action because the limited safety benefit gained does not justify the high cost
of equipage.