My point about leaving something in the receiver is that a rear end impact will focus all the energy at the receiver square instead of spread along the entire hitch beam. Will it make enough of a difference in the end? I don't know. I just don't want to add a focal point to the hitch (bumper beam).I thought about doing the same until in another thread they mentioned that leaving the actual hitch on would cause a lot more damage to your vehicle in a crash. The impact wouldn't be absorbed by the part of the bumper meant to take a hit.
The weather tech is what I looked at first. It can be found for a heavily discounted price for prime members or @ Walmart. After reading reviews about it breaking off due to a parking bump or trying to use it as a step I searched for alternatives & found the superbumper option to be superior. Those have a system of rubber inserts that compress 3" in a hard impact. @zulater has a valid concern, but if you are going to use a hitch insert anyway one that cushions impact is the way to go.
Can we see a picture os how it looks on your Ascent?See link for another option for hitch accesory. Small shop offering hitch inserts that offer some cushioning in a crash or backup situation. Called in left message, Jeff returned my call & worked out details. Had my rear protection plate soon after that, about same width as removable cover.
STOP Rear end Collision Damage & Reduce Whiplash Injury! SUPERBUMPER