Originally Posted by
findark
A ticket to IAD includes "access to" the area outside the sterile part of the airport. You (normally) don't access it when transiting.
Who says that? If I buy a ticket transiting through IAD, I'm not allowed to go out of the security and meet some friends and come back in later?
You may have a better argument if IAD charges $10 on terminating passengers, but not transit ones. But that will be purely between the passenger and IAD, not passenger and the airline. That's like paying state sales tax on stuff bought from a merchant who forget to charge it automatically. You can write a check of $10 and send to IAD and that should suffice.