[contingencies]

Requirements are almost never perfectly specified. One of the most substantial and hard-learned parts of good systems design is automatically pre-empting, as far as reasonably possible, the probable range and depth of requirements scope shifts over the project lifetime. (Critically, that includes the 90% of a project's lifetime which is post-development maintenance.)

In short: if you have good people it shouldn't matter! Experienced people will extend the assumed scope beyond the stated requirements without being asked, and either do so efficiently within the resources available to the project or bring an appropriate level of attention to the limitation before it becomes an issue.

The somewhat less PC and far snarkier explanation, in the immortal words of twitter: Don't pick the right tool for the job, pick the right framework which secures you extra work for being a tool. - @iamdevloper (via http://github.com/globalcitizen/taoup)