What I mostly meant by that is that Campione don't negotiate with mortals: they RULE them. No matter who they are, command from Campione is essentially automatic sentence of servitude to any mortal not MONUMENTALLY stupid, and in case they'd still try to refuse the Campione in question could just order HCC to brainwash them or kidnap their families or whatever to force compliance, and they WOULD do it (with snappy "simon says" joke to boot).
Of course, we are unlikely to do it, but the fact remains that our authority will most likely enable even our underlings to handle all negotiations with normal humans without breaking a sweat, and we don't actually need to pay attention to those.