Watch out for participants who try to stake out exclusive ownership of certain areas of the project, and who seem to want to do all the work in those areas, to the extent of aggressively taking over work that others start. Such behavior may even seem healthy at first. After all, on the surface it looks like the person is taking on more responsibility, and showing increased activity within a given area. But in the long run, it is destructive. When people sense a “no trespassing” sign, they stay away. This results in reduced review in that area, and greater fragility, because the lone developer becomes a single point of failure. Worse, it fractures the cooperative, egalitarian spirit of the project. The theory should always be that any developer is welcome to help out on any task at any time.
— Karl Fogel, Producing Open Source Software