I can see that some of the cities are popping in and out - in the top example, Highland park by the lake in the upper right, and Lasalle at the intersection of

I can see that some of the cities are popping in and out - in the top example, Highland park by the lake in the upper right, and Lasalle at the intersection of 39 and 80, but it's really hard to see them with the labels moving around. Might have been easier for him to make his point if he could add in some red circles around the affected towns. Actual, maybe the cities are being hidden due to label placement? That is, there's not enough room to display all the cities with their labels, so rather than have them overlap, the algorithm chooses to hide the city if there's no room to place it. I bet if you zoom in on a missing city it'll show up.