Passing the Barnes Foundation's sprawling new parking lot one recent afternoon, I was surprised to see half the spaces were empty. By evening, however, the joint was jumping, the lot was full, and many female visitors were wearing skyscraper heels, rather than the sensible flats of the serious museumgoer. That's when it hit me that the real motive for cramming the lot onto the Barnes' tiny site was to help the gallery promote itself as a party venue.