The book is called "Scorecasting" - a very interesting summer read on how judgement calls are made or, more often, not made, depending on the game situation. Humans have a strong tendency to do nothing, rather than to do something and be wrong. Doing something, and being wrong about it, is seen as much much worse than doing nothing and being wrong about that. This could explain why illegal pitches are rarely called, and why everyone gets so upset when they are called.