false clue

He completed his compulsory military service in the Royal Corps of Signals, where he became a Morse code operator, a false clue for fans of the mysteries: Inspector Morse was named not after the code but after Sir Jeremy Morse, the chairman of Lloyds Bank and, like his friend Mr. Dexter, a crossword devotee.

Ackroyd equates a MacGuffin with a red herring, which means almost the opposite: a false clue.

This is assumed to be a false clue.

You may think the scene is some kind of a MacGuffin, a false clue, but it isn't.

Anticipating his value as a beautiful false clue, Dorking laughed uproariously at the sight of him, and readily agreed to buy a French poodle.