Although not car related, over the last 12 years, I have worked on hundreds of small to very large jobs subcontracting to several insurance builders and have had extensive dealings with insurance companies and their assessors / loss adjusters.
Generally speaking, I have often been impressed just how far the insurance companies go to ensure that everything is done correctly and that the customers are looked after. Have even seen it happen many times when they could have got out of paying up on a technicality but did the repairs anyway, even spending $800,000 + on one recent job where they didn't have to.
No doubt, a lot of the reason would be in self interest, as they just don't want negative feedback or to appear on current affair type shows.
If you do the right thing and don't do dodgy stuff, then mostly the insurance companies will play ball. But as you can imagine, there are a hell of alot of scammers out there trying to fleece everyone else with fraudulent claims, and in the end, its everyone else who pays for these. So I am happy for insurance companies to just not pay out willy nilly as it means the costs to the rest of us can be kept under some sort of "control".