I don't get this. Sure, what you describe sounds like a precious moment. But why is it "stolen" if some company films an ad featuring a similar moment? I assume you wouldn't have the same reaction if you saw two real teenagers doing this, or even saw it fictionalized in a movie financed by some production company hoping to make money. What is it about seeing it in an ad that crosses a line?
As a teen (and an adult) Coca-cola certainly was not a prescriber. Anything they'd show in their ad would be immediately and correctly understood as fake and an attempt to get in. Action, reaction. Most (and my friends didn't care) would get over it but the moment is tainted by the brand. Everyone has a different line not to cross though.
Now my line is that this scene is strong, it has meaning. But it doesn't need Coca-cola for that. The product diminishes the experience, it taints it. Next time we get on that roof, what do we make of ourselves ? But as another poster commented: "what's in the coke ? Rhum or whisky ?" :).
Fair enough, I think I just lack this feeling that Coca-Cola taints something by association. But I suppose if Blackwater filmed a series of commercials in my neighborhood, I'd be unhappy with that association too, so I think I get the logic now.