I have a KLR and as you might know, they shake quite a bit.
A few weeks back i noticed that the mini din connector was about to fall out. It obviously would not as the wires would hold it (till they break).
It was a simple fix to open it up and screw the nut back down. Some of your users might not find it a simple task.
My suggestion would be to simply hit the nut/washer with a drop of thread lock from the back (like most radio vendors would do). Problem solved, and no future repair/warranty requests.