Brian

Most YC's don't require liability insurance
Your point of view is that your club should require it. Ok

The problem is when you require proof to gain entry into the game of racing and don't collect the copy.

If you resolve the issue with a statement on the entry form to the effect of

I certify that I have XXX amount of third party liability insurance.

I suggest this language meets your goals.

You would not open any can of worms and be in line with the EU and not out of line with the YC policy in this country.