Have WoE start/end be announced in-game
So every hour there is an in-game announcement giving a random tidbit of information. I suggest that it be set so that when WoE starts or ends, the announcement is specifically regarding WoE. Something like "War of Emperium has started in Sacred Altar at Greenwood Lake!" at the beginning, and "War of Emperium is over!" when it ends. Anything along those lines, acknowledging it.
It'd allow newer players to be aware of both the presence of WoE and the time it happens at directly in-game, as well just be a more appropriate announcement all around for the time.