[EM] Mike: order reversal incentive in approval?

[James Green-Armytage]

Mike, you wrote:
>In Approval it's possible to benefit from order-reversal that doesn't 
>involve one's favorite. It isn't likely, and it's been argued that its 
>likelilhood is low enough that it should be ignored. 

	This is new to me. Under what conditions/assumptions does approval have
an order reversal incentive? Can you give an example where order reversal
achieves something that cannot be achieved equally well without order
reversal? 

Sincerely,
James