that Moiraine has been to SL before. She seemed familiar with the city, and the problems inherent to the locale.

I also suspect, and this ties in with my SL theory, that, one day, I swear, I'll post, that SL, Mashadar, and Mordeth are more deeply touched by the Shadow than we know.

If this is so, then her Wards would just have to be minor variations on Wards known and used against the Shadow, and those would be taught to everyone in the WT.