On cover score

The cover score is not for being the described thing, but rather for how well one does it in conflict situations.

Therefore one could be cover 1: President. The descriptor's name means the characer holds the office of President of a country; the score's value shows us that he is uncommonly bad at it.

The reason that Cover scores are so high given the character creation rules is because Sorcerer player-characters are intended to be competent in the worldly sphere, even if that sphere is "crappy homeless guy." If you created a Sorcerer player-character with that Cover score, then by golly, he's going to be good at being a crappy homeless guy, if those skills or lifestyle-concerns are relevant to a conflict he faces. [1]

On rolling cover

If acts are not involved in a conflict of interest relevant to the Kicker or scenario in general, you don't roll. That's right. If a character with cover: olympic athlete is competing for the gold, and it's not an issue to the Kicker or scenario in general, then don't roll. The dice are not involved. The score values are effectively irrelevant.

It may be that people want to roll in such a situation, and I contend that if it is, in most cases, this is because the character's success or failure is relevant to the scenario, i.e., how he deals with success or failure, and how that relates to later decisions during play. In which case, you do indeed roll, because it qualifies. [2]