Jam nuts serve a purpose and that is to prevent actuating arms from becoming disconnected. I found three examples on the same airplane. Two flap jam nuts were loose and should have been caught on a preflight, and the autopilot servo arm jam nut was loose as well. Any of these could cause a flight control problem if they came completely loose.
In Case You Missed it
Fixed Formation
The Bel-Aire 4000 flies on lower wings from a Piper PA-22 Colt and upper wings from a PA-12 Super Cruiser.
Pedal Power
Building a classic biplane for the next generation of aviators. By Tom Brusehaver.
Loctite and safety wire , I have yet to have one come loose