Foul Definition Help

[referee99]

Made the mistake of doing some reading of the rules book last night.

4-19

Art. 1... A personal foul is a player foul which involves illegal contact with an opponent while the ball is live, which hinders an opponent from performing normal defensive and offensive movements. A personal foul also includes contact by or on an airborne shooter when the ball is dead.

Note: Contact after the ball has become dead is ignored unless it is ruled intentional or flagrant or is committed by or on an airborne shooter.

The only situation where I can imagine a dead ball foul on an airborne shooter is on a dunk or maybe a tip, and the note suggests ignoring the contact unless flagrant or intentional.

Why d'ya suppose the 'or on' is included in the definition?