Here's my situation. I'm pretty much cruising towards a research (or alliance victory). I've managed to out-colonize my opponents (and got lucky finding lots of good planets to colonize). I dominate the galaxy in every way... and I have an alliance with the Arceans and a bunch of highly lucrative trade routes with them. The Drengins are on the other side of my huge galaxy and are little threat.

Then all of a sudden out of nowhere I get this event where the Arcean leader gets assassinated by a "disgruntled worker" when visiting my empire. This causes my ally to declare war on me, cancel all my trade routes, and screw up my game... I had to revert to an earlier save.

I love the concept of events but this one goes a bit too far... Is there some way to exclude game-changing events like these from triggering?