Not necessarily. In my teen years, a man exposed himself to my friend and I. He was in a car, we were walking. Called police. They caught the guy via "radio net" trying to leave town. Yep, we could describe his funny underwear too.
Childnappers can walk with child, away on foot. I think a lot depends upon where you live.
In your case there was evidence of some wrong-doing. That wasn't the case in this instance.