The bolt has to be tightened so much to get the slack out of the bushings that there is just no way that the nut is going to come off and the bolt fall out. Additionally the nut has a bit of a locking edge on it. That bolt is just not going to come out. Have you ever seen a nut come off that bolt even if the bolt is in from the top? It ain't gonna happen if you tighten the bolt enough to take out the slack, period.

To me there is almost no chance of the bolt coming out on my car anyway because at every oil change I pull on all the steering linkage to see that it's tight and that nothing is leaking or falling off. That's why I don't use a topsider.

Good luck,