Has an AFL game ever ended 70-17?
Exactly once. On May 14, 1898, Essendon beat Fitzroy 70-17, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 70-17 in league history.
That makes 70-17 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 71-17 has happened never and 70-18 has happened never.