Leaving early has worked for me.
Art Opening are not usually Bacchanalian drink fests, in my experience. The crowds and general lack of seating and little or no food doesn't lead to long visits. Although, the temptations exist. It's a really good sign you are being preemptive and preparing. You can also decline to go.
As they say, we have little defense against that first drink. But you are showing some defense now, while there is still time.