Watch Your Kids

Yesterday I brought the kids to the park that's near our house. On our way home, I was driving down a side street and only going about 15 miles per hour. As I looked ahead there were 3 little kids playing very close to the road and of course with no parents in sight!! As I keep slowly driving closer, the little girl who is about 3 years old decides to walk into the middle of the road and starts walking straight for my car!!! I immediately stop the car and put it in park and open my door. STILL NO PARENTS!!! However, there is 2 ladies taking a walk and I ask them if they know the children. They answer with a very brief "no" and keep walking. The first thing that pops into my head is, "seriously, I could be a child abductor and you guys are just going to keep walking!" The little girl then walks up to me and says, " Hi! My name is (can't remember it now)!" AGAIN, STILL NO PARENTS!! I tell her she needs to get out of the road and get back into her yard. Her brother then decides to come and get her and help her, but still he is only about 7. I didn't know what to do. Should I go knock on the door and tell the parents that they need to watch their kids or they are going to get hit or stolen? Do I call the police? Next time the little girl might not be so lucky. Finally, I just made sure she was safe and drove away. Now I'm kinda wishing I would have knocked on the door!!