That's one of the reasons Zen (and others) have modded the luck scale.  Unmodded, even a positive luck scale in effect 
increases the likelihood of bad events, since it causes more events in general, while not causing much of a bias towards good events.
Even with Luck 3, I've seen two horrificly bad events happen in the same early turn : pre-turn 3, the temple burns down 
and my capitol lost 50% of its population.  Oooh, I felt 
LUCKY!!  
