Originally Posted by
HofstraJet
I'm guessing to prevent people from booking a lower cost routing and then switching to a higher cost routing (e.g., nonstop). That said, I don't think this would apply for standby since, as you mention, that seat is going out empty anyway. But I think it's also about training customers to buy what they want and not try to game the system by booking lower cost fares and then switching them.
Curious to hear others chime in.
I could've sworn that someone else posted in another thread that it's same routing since it only required a re-validation of the ticket versus a full re-ticket if changing routing. Someone also posted a speculated report that each re-ticket costs AA some stupid amount to Sabre as part of their overall PSS agreement.