They will flex up into the tub and cause the damage you are trying to prevent. And there is a distinct possibility that they will pull or damage the threaded holes in the torque box for the body mount bolts. The leverage is insane, not in favor of the body mount bolt, and wholly in favor of the step. I have removed several sets of them after I had the owners watch while I hopped on them and they flexed. I only noticed it because I watched the owner get in and the step flexed. He planned on wheeling in the rocks a bit, nothing major and after he saw the movement, he opted for a real set of rock rails in favor of his steps.
My phrasing was calculated and precise. Steps are not the same function as rails. If you want rails and intend to use them as such, do not use that bullshit mounting system.
Bear in mind that there are vast differences in dynamic versus static forces. Drop a tire off a rock and land on that step and you will regret it. If you are never going to do that, enjoy your step no harm, no foul.