Para misunderstood my post. Sure there is a rule against it saying you drug dealers cannot backstab and whatever. However that's clearly not what my suggestion was about. If they are friends and are basing as gangsters they could potentially backstab each other. Which is what i was suggestion you shouldn't be allowed to.
Again if you don't trust them make them drug dealers, but if you DO trust them they should still not be allowed to backstab, cause it in a sense ruins the game for everyone else that's basing. Also im sure they could be a drug dealer job limit so it only has a bunch of flaws to it.
Either way my suggestion has currently alot of support and should remain unlocked for others to vote on.