I knew WN was exaggerating when they described the international systems as running "perfectly" or whatever optimistic adjective they used.

re: Having to reissue boarding cards: Last month I had no problem (along with the handful or so of fellow transfer passengers) while going MEX-SAT-HOU with boarding passes issued and printed at the ticket counter in MEX. Perhaps this is a BWI problem or perhaps MEX is using a different system or something.