Going back to the original question, should the situation occur I am sure it will come down to individuals making their own decision whether to race on a salt treated track or not. What I would expect is for the circuit concerned to advise competitors and organisers of any treatment so that they can make their own 'risk assessment'.
Running something rare and valuable from the 60s / 70s, with alloy tub / body, perhaps riveted with steel rivets to a steel spaceframe, magnesium castings, and everything rose jointed would be a bit different to running a modern production saloon for instance! (If anything like the latter exists, that is!)
