The people were not randomly selected. We are not told what their instructions were. We do not know what their relationships were with the creator/subject of the piece. None of that is a "problem" with the piece, of course, because it doesn't even purport to be science. It's not "performance art" in the sarcastic sense that you might apply to a very poorly designed social science experiment. It's actually performance art. It tells us as much about humanity as an indie film depicting the same occurrences would.