I don't particularly want to target you directly SterFran but there's something about the wide-eyed "Oh, but it's all good fun, like nature intended & I've never seen any trouble" that's really concerning to me.
Any place where children and women are naked will be targeted by men who find it sexually arousing. There are some places where we have to be more or less naked - in the bathroom, at the doctors etc. but a naked family swim event is not one of those. For whose benefit is this event? The kids? I doubt it. Adults who like taking their clothes off are prioritising their pleasure over the privacy and safety of children.