the way i understood it was.... for example:

i've just overtaken you , we both go around a corner, i spin and my car takes yours out. your insured and i'm not so you can't claim off me, if you wanted a pay out, you'd have to claim on your own policy.

i'm probably wrong, its just how i always thought it was, especially considering the majority of trackdayers don't have any form of insurance so if 2 of those come together its a knock for knock, shit happens outcome.

its sensible not to risk it anyway, not having a dig or anything