I'm late to the party, as usual, but I'm firmly in the don't go camp. I've tried active intervention in my limited experience with people telling me about bad situations, and have had no luck. At all. At this point, I have to state my opinions and let people make their own decisions. Most of the time they don't do what I think is right (typically leave the situation) no matter how hard I persist or even intervene. Accordingly, I state my opinion and let them lead their life.
Also, it should be noted that I have 500 acres in the middle of nowhere. And a backhoe. Just sayin....