The latest post on the blog Jeremiah’s Vanishing New York, “Attention High Line Tourists,” demonstrates well one kind of reaction to the impact of tourism in cities: signs warning tourists to tread lightly in surrounding neighborhoods. The High Line, of course, refers to one of the most decidedly “in” places to “do” in Manhattan: a former elevated railroad right of way recast as a linear green space three years ago. The High Line works as a tourist attraction not just because it affords a new perspective on the city but also because it passes through neighborhoods that promise steady use and points of interest. Yet the High Line isn’t an unalloyed success in everyone’s eyes. If artists are often the spark that ignites gentrification,…