Regarding insurance....
we bought our aeroplane from an insurance company following a landing accident (and then went and rebuilt it to as new). But the interesting thing is that during the rebuild we found several things which one would have thought should have lead to an invalid CofA - for example lifed hoses which had never been replaced and had no markings on. The previous owner received a full settlement.
So this leads me to believe that actually the insurance companies don't look very hard trying to find a loophole, I think the surveyor came down, spent half a day checking paperwork and seeing that the aeroplane was indeed beyond economic repair and signed on the line rather than a full technical audit.
Maybe it is different if your aeroplane is worth half a million?