Like what age?(Should dogs not be left alone with)
I think they should only be left alone with large children, maybe 12 years or so, that are able to control the dog and by then understand a dog's body language and stuff...but this only applies to children who OWN the dog...I don't think that strange children should be left alone with a dog that isn't theirs, whether they are old enough or not...

I was always left alone with Leather, when I was little and now...
It wasn't right when I was little, but I never thought of it then...She's a great dog though...She loves kids, but now that she's older, we have to be even more careful than usual, as she's becoming less patient...

They mistake our body language sometimes and beileve they are hostile actions.
My dad used to pretend to beat me up lol..and Leather would freak She couldn't bite him, because he's her daddy, so she felt like she couldn't help me, so she would just bark her head off....then we would tell her she's a good girl for protecting me