As might be guessed from the wiki page I made:

http://www.birthright.net/brwiki/ind.../Random_events

I'm quite a fan of random events, but on a 'does it sound fun, then lets have it' basis, I'd generally auto-resolve any that came up during a busy patch or that the pc's weren't interested in doing.

I'd make random events more common for domains that are large, complex, or both for a variety of reasons, not least of which is the need for a large domain to fragment via strong vassals (i.e. interesting npc's).