As a corporate travel agent who books business people into and out of Washington, I find this disturbing on a couple of levels. For one thing, some airlines (Southwest) will debit a travel agency the cost of a full fare ticket if they let a reservation go unticketed by the time the flight departs. Other carriers merely mark ticketed reservations that are not used (“no-showed”) as valueless for future use or exchange. On the other hand, I have access to some elevated customer service desks on certain carriers (including Delta), for which I have occasionally been really, really thankful. Delta…