I think it's very situational, and if you don't meet certain prerequisites, the canon wars it initiates don't happen...

I love this mod, but due to my work schedule I haven't had the chance to complete an entire playthrough. That said, both the Romulan War and initial Klingon War both began as scripted events, regardless of any of my involvement or relationship with either power. I should note that the Romulan War began with drone ships attacking my planets (as seen in Enterprise's final season) and, through an event chain, I learned the Romulans were responsible. I then had a choice between declaring war or not.

I'm thinking this is why the Vulcan's and Andorian's went to war shortly after P'Jem as well, it started after an event popup.