I have these occasional little encounters myself. It leaves a bigger impression on me when the girl is both rather young and also confident with people older than her.
I was somewhere last week, a little tan girl about 7 walking ahead of me toward a line. We were both even at some point, and trying to be a gentleman (and to take her in with my eyes), I gave a little bow to her and waved her ahead. She had a cute little patootie. She paused, looked back at family, and eloquently said "that's okay, you can go ahead of me, I need to ask my sister what she wanted." I thanked her. Just a little moment. It's nice when a girl that young can actually hold her own, when these days even girls in their teens will have their arms folded and look awkward and not know the simplest of social interactions with adults.
That reminds me, I had a strange but pleasant dream last night. I was with family at some rural lodge with multiple little cabins. My key was gold in the shape of a beaver with its tail out. It was a lovely forest setting, but I kept leaving to go visit this other cabin, because there was a little blond girl about 7 with deep brown eyes, in a bed, wearing a spaghetti strap tank top, and she would sit up to hug me with her top hanging lower than her nippies and a bare belly. I don't know who she was, but she was very soft just like my pillow. Some annoying 20-something worker dude kept barging in, asking if we wanted new sheets or something, and I kept frantically waving at him to leave. Then I would have the recurring thought of do I do naughty things with her, or do I not? I really wanted to, but I think my pillow was relieved that I never got around to making sexy-time with it.