PSA (Pacific Southwest Airlines) used to do something like this.

They had a promo where your secretary or other that made travel plans for you also earned frequent flyer miles!

In fact, they had a great TV commercial on this promo. It was very funny and I often think about it when I think of Mileage/Segment runners that go waaaay outta their way to earn miles.

It starts off with grumpy secretary denying a request from her boss to book a ticket, and ends with her delighted to book not only a ticket...but a ticket from here to there to here to there to...well...you'll get the idea. Enjoy.

http://www.cactuswings.com/psa//snd/psa6.wmv