The FAA requests public comment on removal of the current transponder exception for gliders. This action responds to recommendations from members of Congress and the National Transportation Safety Board. The purpose of this action is to gather information to determine whether the current glider exception—from transponder equipment and use requirements—provides the appropriate level of safety in the National Airspace System.

https://www.federalregister.gov/article ... or-gliders

If this goes thru, it won't be long until they go after powered aircraft without electrical systems.