How far can kids push the line these days

Driving back from lunch yesterday, i happened to notice a young kid on a bicycle riding around. About to mentally commend him for at least wearing a helmet and obeying the "no walk" sign, i suddenly realized that this boy of probably less than 10 had in his had a red bull, one of the large versions, dwarfing the hand holding it. The boy takes a hearty swig, and looks around him as if trying to see if anyone noticed him looking cool and acting mature by drinking the overly caffeinated drink. He saw me looking at him, and i guess my expression must have been rather severe because his face went from smug to guilty in about one second flat. He crossed the crosswalk, occasionally glancing at me to see if i was still watching him. On the other side there was another professional looking bicyclist. When the boy pulled up next to him, the man also noticed the Red Bull in his hand and gave him a disapproving look as well. The kid dropped his hand so the Red Bull was behind his leg and out of sight.
I'm not against kids acting mature. I become concerned when they're consuming products that are not good for their system, in an attempt to "be cool". And dont' go telling me that Red Bull isn't that bad. It's high in caffine. And 99% of kids... DON'T need more energy. I would like to believe that it's not possible for children to buy a Red Bull, that the store clerk would have enough of a moral code to say "no, you can't buy that unless your parents say it's ok". But it's probably not true. Though, in all likelyhood, the kid probably snuck the Red Bull from the pantry, or an older sibling.
And that brings up another issue of my concern. I'm all too aware these days that kids steal even from family. A feeling of entitlement that removes all sense of shame and remorse. I wonder where it will end. When kids will try to lead happy, healtful lives instead of conciously pushing the envelope in order to unconciously get attention from the adults who ignore them.
I don't know this kid. I don't know who his parents are, or what his home situation is like. I can only assume that he is trying to be cool and mature bassed of the few moment's of behavior i noticed. I can only hope that two dissaproving glares had some effect on his decision to drink the rest of that Red Bull, though it's more likely that it will only encourage him.