I suppose the boxes might have been moved in anticipation of the Red Sox victory parade. What's weird is that all of the other press boxes are still there. I could speculate further and say that all of the other free rags managed to get their boxes back in place and the Phoenix dropped the ball. I don't know.
*For the non-Bostonians here, those would be Park Street and Downtown Crossing. The closest box I could find was a full stop away on a different line. At a little over a quarter of a mile, it wasn't an impossible walk, but it was an interesting one.