ohms_law, it's still in the unit & model files. I have no way of knowing if the game engine is still using the tag, but it should be easy enough to see in the game.
http://www.ageod.net/agewiki/Home_AreaAssuming that information is still current, there are bonuses and (mostly) penalties which you may already know.
HOME AREA PENALTY/BONUS
// see HomeArea at the model level
areaOutsideHomeAbi = -1 // -1 level to abies (can render them inactive)
areaOutsideHomeStr = -2 // Strategic
areaOutsideHomeOff = -2 // Offensive
areaOutsideHomeDef = -1 // Defensive
areaOutsideHomeTQ = -3 // TQ (and 5 time that to max cohesion)
areaOutsideHomeMR = 66 // Move Ratio Coeff (x0.66)
cohLocalAreaBonus = 10 // bonus to max cohesion if at home
I think the biggest hit to raiders would be the movement penalty, since that's one of their best attributes.