A beverage or two during a game has never been a problem for us, though every now and then one of us will go a half step over the "good idea" line. Two weeks ago one of the guys brought a beeer he hadn't tried yet to the table and had at. It was a lighter beer (tasted a lot like a barleywine, actually), and they went down quickly, so it came as a bit of a surprise when this guy started off down a tangent involving the creation of tiny mithral plate mail armor and his pixie army. Since we were in the middle of a fight when he went on that off topic binge, we tuned him out long enough to get through the fight.
After the fight, he scanned over the label on the bottle, saw that it was about double the alcohol % as most beers in the US. He sheepishly told us, said "no wonder I'm talking about pixie armies," and we all had a good laugh at his expense.
But now I have this sneaking suspiscion we're going to end up having to deal with a well armed pixie army some time soon...