I just did a wedding last weekend completely sober. What worked for me was always keeping an non-alcoholic drink in my hand. For me there's definitely a habitual aspect to my drinking. I used to smoke and whenever anyone lit up a cigarette I'd always have to light up too. Same with drinking. If someone's standing there taking a drink, I just feel compelled to take a drink as well, regardless of what I'm holding. Also, as everyone else said, make sure you have a way out. If going by car, try to drive yourself. If not check bus schedules, train schedules etc. As soon as you see things getting out of hand, get out. From my experience, albeit limited, there's nothing potentially more dangerous than being stuck in a sticky situation, feeling anxious and trapped.