From what I've been reading, it seems like the FAA either doesn't understand what control line is, or they just don't care. Why doesn't an AMA rep or 2 meet with a FAA rep or 2, show them a scale and a stunt control line model and say: "This is what they are." Then show them videos of a scale and a stunt flight and say: “This is what they do.” Then make the comment: “Now that you've seen what control line models are and what they do, I'm sure very smart people like yourselves can agree that they don't need to carry transponders and should be specifically excluded from FAA regulation.”
If this has already been done, and they still insist on regulating control line, then our future indeed looks bleak.
This is the comment I wrote, but I won't actually post it if anyone thinks it will be counter productive:
“Please make an effort to familiarize yourselves with the difference between a control line model aircraft and a drone. I have been flying control line model aircraft for 61 years. Their flight is not controlled with a radio and they are not drones. They fly on lines made of steel or synthetic polymers. They are powered by small internal combustion engines or by electric motors. Their flight envelope is restricted to the surface of a hemisphere whose radius is the line length, which does not exceed 70 feet. They are always within the pilot's line of sight.
The lines are attached to a handle held by the pilot. The handle is attached by a safety tong to the pilot's wrist. All components are pull tested for strength based on the model's weight. The model cannot fly either a horizontal or a vertical distance away from the pilot greater than 70 feet, even if the pilot becomes unconscious during the flight.
Control line model aircraft have been flying for nearly eighty years. In that time they have never posed a danger to general, commercial or military aviation and they never will. Therefore it is completely unnecessary, as well as existentially impractical, for control line model aircraft to have on-board transponders. Furthermore, they should be specifically excluded from all UAS regulations and their pilots should not have to register.”