@Patti191 Does your insurance cover your str or is it just your normal homeowner's insurance? If it's for your rental, ask for clarification from the insurance company.
What age children are you talking about? Are these young children or teenagers? 13 year olds can legally babysit, meaning that not only are they alone in a home, they are responsible for the kids they are babysitting. So I think a lot of parents wouldn't think twice about leaving kids that age and older alone, I know my kids were home alone sometimes at that age.
So the best thing for you, I guess, is to not only have that rule in your listing, but reiterate it in messaging to guests with kids when they book, and remind them of it when they arrive. Just say that it's a condition of your insurance.