I don't know what counts as "heavy drinking" on a flight, but I am a drinker. And when I am in a position to get "free" drinks, I take advantage. I mean, really, that's one of the main tangible benefits on domestic F. Free booze. For long haul international, the choices of "free" booze can be pretty damn good. People have already mentioned top shelf champagnes and things that they may not otherwise ever order or buy on the ground. And if you are buying a coach ticket and upgrading with SWU/eVIP or something, then it gets closer to free. Also, same goes if you get the seat with miles.

But I rarely drink in coach. Usually, because I don't want to pay for a drink. (though as EXP on American, they would give me a free drink when I was back in Y)