I agree with you on the emergency brake away cable.
It should only activate if your trailer comes off the ball AND chains cause
if it engages early, it could brake the chains or at the least, cause you to
loose control as the trailer brings you to a sudden unexpected stop.
Where the numbers come from.......Beats me.
Wear and tear on the ball makes sense to me. I would just toss in that it
needs to be inspected every time you hitch up and tested for proper locking
by the same method you suggested.
If the ball looks worn, Best to replace it. Also the inspection should
include the ball socket. If worn, Fix or replace.
--
Warren
1989 GMC R2500 HD Suburban.
1953 Airstream Cruiser Travel trailer.
Western KY
> It is generally a good policy to pick up the back of the truck a bit with
> the tongue jack. Shows the coupler is locked properly, and also makes hook
> up easier if tensioning weight equalizing bars...... snip....