Good call! I've been meaning to lock mine down too, but keep forgetting to find the screw.
FYI for anyone considering doing this:
If you are not using the locking screw that came with your Kiox, please make sure it does not apply any upwards pressure on the Kiox display itself. In the past, some screws that were longer-than-stock would push up on the display, causing poor contact and intermittent cut-out. Every so often, we also recommend removing the screw, sliding the Kiox off, and gently cleaning the contacts. This will help prevent any unwanted corrosion that could potentially cause intermittent cutout in the future.