Yes, and I'm saying that that does not make him a pedophile. I see fathers kissing their young kids on the lips all the time, maybe it's a European thing? Unless he's using tongue I don't see a reason to call the cops.
As to your question, I guess it depends on the person. I wouldn't mind if it was a women for example. If it's a guy, I'd at least go have a chat with him. If I wasn't happy with the situation I'd ask him not to kiss my boy like that or tell my kid to avoid him. I'd certainly not assume he's a child molester right off the bat and call the cops.
If one of my neighbors saw something like this happen and let it slide, I'd be absolutely furious with them.
What a world we live in. Not that I disagree with you, but what a world.