people do not understand dogs, people think the dog is ok with them so it will be ok with everyone...wrong.
my first dog was a small cross, i have never seen a more loving dog or one that everyone loved, she was well known around the village and if she was around without me she was welcomed at a couple of houses.
she had been around kids (babies, toddlers and up) and never got 'angry' with them yet even she took off after a lad that ran past she was growling and barking, the lad stopped and she turned back and returned home...the lad knew me and her very well and was more shocked that she had shown this completely different side to her.
now, had she been a rotty or bully etc it could have been a much worse story but it taught me that you can NEVER be sure, they need to be trained and they need to be shown respect.