I've updated
my plan to include navigator genes and exclude berserk gas. Notifying Chaos is still completely off the menu. People, I think, are forgetting that they are Chaos. They do not prepare for threats in the same way, by just hunkering down and fortifying. They will likely raid for slaves in preparation to conduct grand rituals and do other evil Chaos shit to other polities in order to increase their odds of their own survival, even at the expense of others.
I am also leaving aside the possibility of trading human souls to the Sirens. Many of the other polities of the Imperial Trust would already be very uneasy at the idea of us trading for xenos warplore. Now is not a good time to throw further fuel on the fire by suggesting that we should start feeding them cultists as well. If we ever start doing that, we need to ease into it. We already have a reputation for radicalism and it increasing it will only hinder us more.