I can see why companies like the AA & RAC dont want to get involved in this sort of thing. They are there for 'accidental breakdown' they arent there to help people who have driven their cars in a manner likely to cause problems.
The fairest thing to do is put a surcharge on cars that are collected from track days or places like Santa Pod.
You've broken it... so why should they fix it or recover it ?
If you've had a failure on track you pay a £50 additional cost to be recovered home.
Same as any other insurance, you want track day cover, you extra for it.
On the other hand you could argue that there are some people who dont maintain their cars properly and rely on the services of the AA / RAC to keep them on the road.
So this could be deemed a similar thing to willfully putting stress on your car likely to cause damage.... and I beleive this is one of the reasons you are limited to the number of callouts a year before you are charged.