the issue is that early A2s simply don't have an authorized towing weight from the factory. Which means at the very least ordering a new sticker from Audi, then getting the Part 1 reprinted, which generally means a visit to a testing station of choice to show what you've done.
For later A2s, the weights may already be in the Part 1, so there's no real issue there. I do not see the point of trying to make something for this, because the safety-criticality is enormous. It's a towbar for pulling a 1000kg trailer. If something happens, any insurance company worth their salt will be looking for a way out, and I personally prefer not to offer such an open door.
Here, I wouldn't have to show the bar at the inspection. In Germany, oh yes. But papers are required here for all sorts of other things.
This is one of the places where I'm happy that standards are set and should be adhered to.
- Bret