Let's say you're at a friend's house for a party. You and your friends all have kids between the ages of 1.5 and 7. You hang out downstairs and on the patio outside. The kids are upstairs. Would you feel comfortable with your child playing upstairs with no supervision? At what age would you feel comfortable with this?
Note: There is no child-proofing in this house because the kids are all on the older side.