Good point about the insurance policies. Although nobody seems to mind people playing stereos at insane volumes inside their cars.
Koss makes several hang on the ear models. The Koss KDE 250’s I reviewed don’t block outside sound, and once you get them dialed in to your ear measurement, might work pretty well. I still don’t like the idea.
I knew someone who used to keep a sound effect tape of an awful crash queued up on his cassette player. He used to use it to end conversations when people called him on his cell in the car. (I think at the time it was a bag phone car phone).