I don't think it is theater either.
The Premise: Etiquette is Theater
For this intimate piece of participatory theater, two museum visitors sit across from each other at a small table...
The response from theater critic Gail Burns: No, it's not.
…Etiquette failed to qualify for lack of an audience. I wanted to see a) if there was anything worth watching, b) if there was anything visually provocative that would cause other people in the café to watch, and c) if people actually did watch. The answer was “no” on all counts.
Points to Mass MoCA for trying this, but it is a new form of social networking in which you come in contact with other people in a ultimately meaningless way.