There is one sentence at P120 5.3 Define scope (PMBOK 5th) confuse me a lot, it says:
The key benefit of this process is that it describes the project, ..... by defining which of the requirements collected will be included in and excluded from the project scope.
My question is that what kind of requirements will be excluded from project scope? Can you give me an example?
If one requirement was exclude from scope, should it keep staying in the requirement documentation? or should it be deleted from documentation?