I have been at a leisure centre this morning while my ds played tennis (one of these holiday type activities). Guide dog lying on the floor next to me doing nothing...
There were lots of people with other younger children there. Anyway a toddler (I would say about three) came over and I heard him running back to his mother saying that the dog had licked him, she laughed and found it cute/amusing. Heard something behind me and dog stirred, so I reached down only to find this child trying to stick his fingers in the dog's mouth. I turned around and said somewhat sharply "now leave the dog alone." at which point the child ran off back to his mum who said nothing.
Now, I don't mind children talking to my dog, but IMO the same rules should apply as pet dogs i.e. you ask before stroking a strange dog.
secondly, if my dog had bitten that child, it would have been perceived to be the dog's fault, and at the very least he would immediately have been withdrawn as a guide dog, and possibly been destroyed given the potential public outcry.
And just to add (as I know how these threads go) the mother was way over the other side of the room, so no way I could have said to her to get her child away - much quicker to address the child. But she knew the child was harassing the dog and did nothing.