In the park today with my dog, not my most regular park so don't know anyone there although people are generally friendly.
Sitting on a bench throwing a ball for my dog when a man and a small child came towards me. The man asked if his daughter could stroke my dog (we're very used to this as dog is smallish and fluffy).
After the little girl had stroked the dog for a while the father told her he was going to the loo (we were sitting near the cafe) and asked her if she wanted to go with him or stay and talk to my dog. She said she'd stay and we had a nice chat, during which I found out her name, her birthday, her age (2 years) and a few other bits and pieces; he wasn't gone long, but long enough to wee obviously.
When he came back we chatted a little bit more and off they went.
Now, I'm a respectable looking woman, I think, and it was about 4.30 in the afternoon in broad daylight in the middle of a public park. The town is generally friendly and safe and obviously the father felt his child would be fine to be left, so aibu to think it a bit odd to just walk off and leave your 2yo child, albeit a very grown up 2yo, with a complete stranger?