It isn't just clubs that are control freaks on this issue. The same arbitrary requirements are found at group rides that are not "club rides" but rather are run by various organizations making like monkeys and following the lead of the club ride honchos. For example, the Bike Ride on the Lake Shore Drive in Chicago, which was not a club ride, required helmets even though there is no city or state ordinance requiring such equipment. I believe most of the charity rides have the requirement too. In my area a bike week weekend ride sponsored by a state organization pulled the same stunt; no helmets - stay away it's not bike week for your kind.

It seems that RAGBRAI is the last holdout against the Nanny/PC storm troopers on this issue. They may encourage helmet wearing but don't require it.

"Insurance" requirements/excuses are most likely bogus excuses for mandatory helmets for any non competitive rides unless the government entity requires it in the specific location of the ride.