Lucy McKenzie must have opted to title the group show she organized “Town-Gown Conflict” well before the summer, so it would be unfair to twit her and her collaborators (or Beatrix Ruf, the exhibition’s official curator) for not predicting the flare-ups of real-life, class-based urban violence that took place in the UK during the exhibition’s run. Nevertheless, the lack of fit between the show’s casual allusion to class conflict (and its introductory text, studded with portentous references to “social differences, educational shortfalls . . . segregation and the demonstration of the superiority