atate2007

reason is they are all together only when you write in your booklet.
Grading process - all the papers are split up and distributed to graders, who are assigned to each question / part of a particular question . So they need to know which question you are answering. Only the lined pages + template pages (and none of the question pages where you may have marked / written stuff / notes is provided to the graders.
It just makes sense to MARK and LABEL what you really are answering, as janakisri stated above.