Ever seen a random flat, sharp, or natural symbol next to a note? That's called an accidental. Accidentals are notes that do not exist within the provided scale. They are used to help raise or lower the pitch of a note that generally played a different way through the rest of the piece. If a set of parentheses surrounds the note, we call this a "courtesy accidental" to remind the reader of the correct pitch if the note appears multiple times in a measure. The comic assumes courtesy accidentals undermine their intelligence because they assume that the reader cannot remember the original scale.