Has an AFL game ever ended 81-15?
Exactly once. On May 24, 1900, Geelong beat Melbourne 81-15, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 81-15 in league history.
That makes 81-15 the 3883rd most common final score out of 6,649 that have ever occurred in AFL. One point away, 82-15 has happened 1 times and 81-16 has happened never.