As said it's not the losing of your car that is the issue, most of us could and do live with the risk on UK Trackdays that if you stack it thats that. Lots of us use a cheaper track car for this reason, some people use a 20k + car on finance, stack it and carry on paying for it long after it's gone to the scrap yard.
The ring issue is far more complicated, forgetting hitting the barrier paying for it and losing your car on a TD, its about the liability issues on TF days. Lets talk worst case, if you were to kill another party and your car was indeed not insured " on the nurburgring nordscheife" to cover the costs involved in this type of thing, you would be committing a CRIMINAL offence under German law. As we are part of the EU and this is criminal and not civil they WOULD be able to come to this country and get you.
Forget all this talk of cliques, there is a very good reason 80% of the people on Northloop no longer drive TF days. Ignore this at your peril, whats the worst that could happen........... ( getting into a plane with ben, not included)