I don't care if you choose not to wear a helmet.
I think that for the most part the issue of riding with others that don't wear a helmet relates to organized group rides. Unfortunately in our litigious society, if you injured on a group ride, not wearing a helmet, it's going to increase the legal risk of the organizers. Also a policy requiring helmets is likely to decrease insurance costs for the Organizers.
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You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.