OK, here?s my initial assessment. The Lock Bar is a CYA Mod, after someone got sued. The case was settled out of court for an undisclosed sum. 8)
After mine fell, for the fourth or fifth time, including once when the dealer first installed it, to show me how, I decided to take a good analytical look. I decided to give my undergraduate engineering studies some exercise. (My degree is in History - same thing.) :
The top of the slide flexes, ever so slightly, as you drive down the road. You can see the bar slack, and then tighten, again as body flexes. It is installed at the top of the slide, on the back of the molding/flange that winds up against the wall when the slide is extended.
I examined the slide. It is not directly attached to the frame, at the top. It appears to slide through a rubber gasket. There are no guides apparent. Basically, it sits on the floor when retracted. If one pushes on the molding/flange, at the top, it is just slightly flexible. Movement not readily visible, just not firm.
If I sit on the floor and push against the flange with my feet, it is solid as a rock. No movement at all, no flex. The bottom of the slide is attached to the frame of the motorhome through the linkage that extends it, and two tracks. Those are visible on the outside, looking up at the bottom of the slide. Pushing and pulling, under there, yields no movement, at all.
If I was fearful that the slide might take off, on its own, some day - I could jam an adjustable bar between the flange and the wall, and prevent that. I could put it anywhere, up and down the flange. Then if the slide starts to move, for any reason, the bar prevents that - or bends the flange or the wall. Or, if the motor to the slide, it stops the motor.
If I put the bar near the bottom, then it is pretty solidly jammed, near the working parts. It is at the strongest point on the frame and on the slide. Only the motor has a chance of challenging it, and I think the motor loses that challenge.
On the other hand, I could put the bar at the top. Then, the slide is hindered, in movement. But, if the slide does start to move, especially if some idiot runs the motor without removing the bar, there is six feet or so of leverage, vertically, between the bar and the solid components and the linkages. Now, if someone forgets the bar and attempts to extend, the leverage assists the motor and something is more likely to bend.
If it is needed, at all, then near the bottom is a better location - head-lumps notwithstanding.
How am I doing? ???
Ray D