I gave a serious thought on using erasble pens considering my horrible writing while doing shweser mock becuase of time pressure and hastiness to quickly write down my mind. While I was doing circle questions I circled, scratched off and circled and recircled options couple time making a big mess. When I reviewed my answers at the end I did not have chance to erase them.
Pencils: Advantage–>Erasable; Disadvantage–>erasable;
Erasable Pens: Advantage–>Erasable; Disadvantage–>erasable; unintentionally erased due to heat, due to rupture even by fingers.
Pens: Advantage–>Not erasable; Disadvantage–>Not erasable;
Erasable pens are most dangerous of all due to unitentional erasing. Legal documents are never written using erasable pens. I consider my exam sheet as legal document in case if I had to submit for a recorrection.
If you must have to erase, go with pencil, assuming you do not have any arch-foes that would scheme to empty your answer sheet. CFA knows that PM is going to be in pencil so it must have certain arrangement that no one tampers with pencil marks, but with AM they don’t promise this. If magically your answer sheet shows up empty they do not bear the risk.
Calm down. Discipline yourself. Follow the instructions. Use pen.