There are several recent fatal accidents where the flight conditions where unambiguously IMC at the point of the crash
I don't doubt it at all, but "us being damn sure" is not the same as the insurer being able to prove that on the balance of probability
1) that the pilot's flight conditions were IMC, and
2) that the pilot had a choice
Insurance does cover negligence, fortunately
I want to see actual cases of where insurance was voided on the basis of alleged illegal flight conditions, or indeed on the basis of anything at all taking place after departure.