Some people don't have dogs, or just don't teach their children from a young age how to handle small dogs. My daughter is turning 3 next month, if we are out on a walk she knows NEVER to touch a dog without asking the owner first, which she is very good at. She will ask " may I pet your dog pweez " and if they are busy talking to me she will ask again til she hears an answer
I have had incidents with children BIGGER then toddlers trying to be too grabby with Stormy at the park or out in public. I usually don't let kids touch her or anyone for that matter because she is shy around adults in public. Occasionally I let some kids pet her real quickly, I always kneel down and show them how to pet a small doggy.
My daughter is pretty good with Stormy and small dogs but of course I never leave them alone together.