The laws where I live pretty much state that anyone that hits someone in the rear is at fault.
That's not always true here.
I hit somebody in the rear, but I had it on video that he cut me off very close and then braked immediately.
Initially the insurance said it was my fault, but I got the police report that said that I was "victim" and insurance agreed to that.
A lawyer for the other person can even claim that your extension past the bumper line was not DOT approved, illegal for use on public roads, and it might win. You never know how those end up. Personally, I don't want to learn a lesson when my car is totaled, so I keep my receiver empty. Everyone does whatever they think best.
And yes, a minor crash that would be absorbed by the bumper, when hit in the ball carrier could transfer directly to the frame and do more damage. Again, the insurance might try to deny that claim because "unapproved changes to the vehicle". Especially if the receiver is non-OE.
What about those with a fixed hitch ?
There is a reason why in US all the receivers allow removing of the ball carriers and they stop at the bumper line. Bumpers are required by federal law and approved for road usage when car is homologated.
The "Vlad ČšepeČ™" impaling devices are not DOT approved
PS: That sounds like "Tzepesh"