There were always perverts and those with ill intent toward children, but it seems to be increasing. I can remember a few people when I was young that we would watch out for. One was a creepy old man who would offer $1 for a kiss. Another was a boy from a troubled family, who used to pull the fire alarms at school. His brother later broke into the house of a friend of mine, tied up her and her brother, and ate a homemade pie their mom had cooling on the window sill. I often think about what happened to that family, because it is so obvious to me now that they must have had a really crappy home life, and I don't think the system at that time was designed to look for signs and intervene.
I'm glad the guy made this video, and I hope it opens a lot of eyes to the dangers out there. The parents in the video thought their child would say no, because that's what they'd taught them, yet they still walked away with him, which is troubling. I agree, each child is individual, and each personality will probably respond differently, so those differences need to be addressed when having the discussion about stranger danger.