+1 to the max. That includes drinking too much. There's only one time I'll limit myself to one drink max, if any, while flying (outside of times when I'm driving after the flight), and that's when I'm going D3. Even if it's inferred intoxication, it is likely to get noted.

If you're nasty with a GA or similar, your buddy who gave you the pass may not be your buddy much longer. The person who gives me D3 passes had a intoxicated friend who got nasty over a gate-checked bag, and it almost cost them their privileges.