> In the middle of a city? If you have someone sitting on land waiting for the price to go up and you threaten them with "not using it," then odds are they'll put a cheap building on it and sell storage space or something. What would that accomplish?

I saw this in action. I wanted to buy an old firehouse for conversion to owner-occupied loft and workspace. Current owner had purchased it in the early 1980's for a few tens of thousands of dollars from the city and the neighborhood had declined-- only half-joking it was the corner of Crack and Stab just down from Needlestick Park. The owner had moved cross-country and left the property and it's value had declined but it was adjacent to a gentrifying neighborhood and a short walk to a city bus stop. When I tracked them down they never responded to calls or letters, the local attorney they had last used had no contact with them, and they had stopped paying taxes. The city finally declared that they would seize and auction it off not because of the back taxes but because the sidewalk was not being cleared of snow and the exterior was unmaintained. Suddenly the absentee owner paid up half his delinquent taxes and let a local guy who repairs cars park vehicles in the bays, etc. Great improvement, now there are beat up cars and junk and the roof has started to collapse but because the sidewalk is clear, it's good.