@Genevieve277
We had a no children setting and we still got a booking request with children.
I read another thread where someone mentioned that Airbnb leave it to the hosts to check who is coming prior to accepting a booking. If you have instant booking on, you might be in trouble.
The search engines let them search for properties which don't accept children, even though they have children!
If you want to accept children, you could add it in the 'additional rules' that parents/guardians must take full responsibility for their children at all times. (I'm in the UK, but you might need to check if this is acceptable in the US.)
Also, when you message them before accepting their booking (to check who is coming), you could add that sentence in, and ask them to confirm that they agree to it prior to you accepting them.