This IS how (some) pedophiles act around children. I know of 4 different people from when I was younger that are convicted, and in the online database showing that their crimes were specifically touching / molesting children (and by children I mean not statutory rape involving a 14 year old).
Of those 4 at least three had the exact same jocular vibe and MO of making contact, the fourth I didn't know anymore by the time he committed the crime(s), so hard to say. Creepily enough all 4 were from church / church camp, and thankfully never tried that shit around me. One guy at camp was forcibly removed by the other counselors and held until he was put into a police car. The others ended up molesting their relatives, but were "handsy" with other kids for years, so since we were at church often, I saw the patterns and strategies over and over, but just thought they were "weird" kids and adults that really liked entertaining small kids.
What (I feel) you are seeing in the video is a guy who had too much to drink, so he's being extremely brazen and fast about his normal routine. Get the kids attention, next playfully touch the kid, gauge the reaction, if the kid seems open to communicating, start working the charm, and then eventually find a way to separate them from their parents. He was oblivious to the dad at first, and I'm betting his intoxication led him to believe the kid was standing in line by himself (as the dad is in front, not beside or obviously with the kid). When he didn't get his attention at first, he went for it again harder, because he just couldn't NOT talk to this little kid, and lets his hand "linger" on the kids back. When the dad turned around he IMMEDIATELY snapped his hand back, in what seems to be fear of getting caught (that's an awfully quick reaction for a drunk guy, it looks like it's been an issue before). Then he puts his fingers / hand on the kids chest. Seriously, drunk OR sober, who does that? Have you ever went up to a kid in line and touched him three different times because you were intoxicated? His freak out reaction also gives me the impression that this is his "secret" (or whatever) and when confronted about it, he just lets loose years of frustration on the dad.
All of this could be off base regarding the guy in the video, but based on past experiences being around them, as well as the patterns given by law enforcement of the MO of a pedophiles routine grooming new children, this IS how they act around kids (at least a medium to large amount of them). The guy in the video is either pre-grooming this kid, or really drunk and made possibly the creepiest repeated contact with a strange child possible.