If I were a teacher, I'd ideally allow this (and the sports fan too, for that matter, if I knew he was a big enough fan).

There's no problem in the ideal form, but I would anticipate a lot of problems in real life - other students not understanding exactly how much this person loved the Exemplars and misinterpreting it as "You get an exemption for going to a rock concert", other students trying to convince you they like [thing X] just as much as this guy liked the Exemplars and you having to judge lots of difficult cases to see if their fandom is truly as great as this guy's is and inevitably getting some of them wrong.

If I really knew what to do, this post would have been titled "Eight Short Studies On Excuses, Plus The Answers To Them"