Has an AFL game ever ended 71-15?
Exactly once. On July 23, 1898, Essendon beat St Kilda 71-15, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 71-15 in league history.
That makes 71-15 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 72-15 has happened never and 71-16 has happened never.