Her parents run the restaurant, so she is almost always there.

She's free to talk to the customers as she pleases as long as she doesn't bother them. I've been friendly and helpful to her plenty. It was her homework that first connected us. She will sometimes ask for help on her homework from customers, and I offered my help once. Who can deny such a cute little girl? She's never learned the whole "stranger danger" concept. Her parents aren't perturbed by the existence of strangers. They're smart enough to know that not every stranger is out to rape their kid, so as long as I'm not doing anything inappropriate, there's no issue. Her parents are actually very appreciative of me and my influence on her.