One thing that can provoke NIMBYs -- understandably -- is zoning changes. If Mr NIMBY buys a home in a neighborhood that is zoned for, say, 20 units per acre, he expects that to remain.

Often a builder requests special permission to exceed the zoning law, and build, say, 80 units per acre -- then solicits public outcry when denied. Zoning law gives owners a legal expectation.