As far as model airplane engines are concerned most (nearly all) of the "engine damage" I have witnessed was the direct result of a crash. But if the engine is out of tune and quits at a really bad time and the result is a crash, I guess that one could be blamed on bad tuning.

I personally always had more trouble tuning glow engines than any gas engine, I guess because I was a piston head from a very young age. To this day, most all of my horses smell like gasoline.