Two reasons: (1) skittishness due to recent postings here that suggest that BA is being almost hostile in its enforcement of SITI and (2) imagined advantage of having a good TA in a far-away place such as Fedex'ing of tickets.

Both reasons seem ill-advised at this point. The TA, in particular, despite being associated with a major trading conglomerate there (or perhaps because of it) is very, very slow to respond, and their worker bees don't pay much attention to detail, thus booking a strangely priced D-class trip when the phrase "AONE4" is clearly stated in my instructions to them.