Initially I though that's why I can't use the Paladin Toaster to silently execute all the BOS in Hidden Valley. But as it turns out the BoS just have telepathic ability which instantly become hostile.
Anyways, than I venture to Camp Forlorn Hope and West Side, using ballistic fist (which certainly would make some sound) to mug unfortunate test subjects; but as it turns out the NPC is unaware the explosion right next to him which send his dog flying 10 meters away.
So, are high tier melee/unarmed silenced weapon or not?