One thing you can do is get a heavy piece of rubber about 3 by the width of your plate. Drill a couple of holes in it and mount to trailer, then do the same thing with the plate on bottom section. That way it can flex back and forth when backing in and pulling out. Like crappie head said, if you have assess to a tool you can get body washers and put on either side and pop rivet them on using aluminum rivets. That way they can't just undo a couple of bolts but when you need to change just drill out the 2 holding plate.