It always seems to be one AI scout that stalks the camp at 2 paces for 10+ turns. Here's what I do when it's a great barb camp. I leave it alone for a few turns and let the barbs stalk that stupid scout and kill it. Then I move back to farming position. It seems when a forted barb is in the yellow the AI switches from "avoid barbs" to "clear the camp mode" since the unit is injured. Just like how if you have an archer at 50% health you can literally place a settler next to the barb and it will stalk the injured archer instead.Barb farming is all fun and games until the AI comes and clears the camp you've been farming.
Because the AI doesn't know how to deal with a barbarian threat with any kind of efficiency. Typical game with Raging Barbs you'll see between 2-3 captured AI settlers/workers and 2-3 CS captured workers. That's between 4-6 "free workers" or if you want to return the non-settlers then some AI "goodwill" diplomacy.
