I worked in a custom 4 wheel drive shop for awhile, and we didn't trust
them, Loctited everything. I used some Nylocks on my personal truck and
ended up double nutting everything I could. When it wasn't in the mud
or water, it was bombing down the roads. I was even pulling the threads
out of the extra tall nuts on the u-bolts that hold the axles to the
springs, so all of those were double nutted with the extra tall nuts as
well. Plus the u-bolts were one size larger than it was manufactured
with. If you wanted to find out if something would break, all you had
to do was bolt it on that truck, sometimes parts would break just
getting near it. So yeah either it's the abusive evironment or just me.

Also, I'm not really clear on how this works, but elongation of the
bolt or stud is how things remain tight. From my understanding that's
why you torque a fastener, to apply the proper amount of preload.