They don't vibrate loose normally. The flat washers are prone to suck down into the holes, if they're not the thick ones and that makes them appear to have loosened when you go to take them off. But agreed, I've never had one vibrate loose. The very left rear is hard enough under the best of conditions, I'd be cautious of gluing that one.
Got half way to work one day and noticed some smoke when I came to a stop.. Realized I had oil on my leg too... Since then, rocker boxes definitly get loc-tite.. Cant think of anything on my bike that doesnt get a dab of one color or another... Blue works fine for me there...