I understand what you are thinking about. Every single person I seem to meet who doesn't drink is either pregnant or recovering. I don't know what industry you are in and I do think some situations where alcohol is being pushed then it can put you in an awkward situation. I go to lots of wine dinners and every social situation I'm in seems to call for lots of booze. The other reason people give is " I overdid it last night ". I might have to resort to that one when I'm ready to go to one. I remember last time I was at a champagne industry party and only one guy wasn't drinking. When I started talking to him I have to admit I was curious and next thing I knew he was telling me that every time he drank a lot he ended up with a baby ( he now has 8 ) and so he stopped drinking!
Some other reasons
I have to get up at the crack of dawn
I'm training for a marathon
I'm doing a cleanse
I'm designated driver