Child Predator?

I've started watching 'What Would You Do' and it got me thinking about one of my experiences.

One day, I was at the library in my favorite section: The Canine Section. A man sitting nearby saw me. He, in my younger, more innocent eyes, looked like he had just gotten out of jail but he was dressed in normal clothing. He started talking to me, and going away, talking to me, and going away, etc. He even gave me a printed picture of a fox in a forest. He seemed really nice, but, to quote Little Red Riding Hood in Into the Woods: Nice is different than good. I had never heard about child predators then, but I got a really strong feeling that I should leave that section. I didn't want to at first because he was so nice and kept giving me things and I hadn't found a book I wanted, but the feeling got stronger so I left.

Looking back, I don't know if that feeling saved me from a really horrible experience or if was for nothing. I do feel like he was trying to trick me into trusting him before he made a move. It's a scary thought which is why I haven't thought about it in so long but I feel like I need to share this story.

Have you guys ever had an experience like this? What would you have done if you were sitting nearby, watching him and I? Do you think that feeling helped?