Whilst I don't doubt the intentions of the organisers, my opinion is that it should be either adults only, or only adults with children.
Do you realise how offensive your opinion is? I'm really tired of the view that if people have children of their own, they are somehow immune from being paedophiles, yet anyone who doesn't have children is automatically suspicious.
Most child sex abuse happens within the family circle :
www.nspcc.org.uk/what-is-child-abuse/types-of-abuse/child-sexual-abuse/
It's common for paedophiles to target single mothers to gain access to their children:
www.dailymail.co.uk/news/article-7665023/Detective-Inspector-warns-paedophiles-using-dating-apps-like-Tinder-target-single-mothers.html
Do you imagine paedophiles commonly choose to be childfree, thus making it highly unlikely they'll have much to do with children or be left on their own with them?
Do you think it doesn't occur to paedophiles that all they have to do is get someone pregnant (or fall pregnant themselves in the rarer case of female abusers) to have unfettered access to a child?
The risk to your child is not the childless person who may attend an organised naturist event - where the children will be chaperoned by their parents.
The risk to your child is the trusted family member who babysits, or the football coach with whom they are left unchaperoned, or your new partner if you are a single mum or even your child's biological father.
The last people you should suspect are those who choose to lead a life free of children.