That wasn't an explicit rule in the meeting, but I'm sure that was part of it, you know. If people hear voices, and they can't see and associate it with somebody, that person's probably not there.
会ではっきり決められた規則ではありませんが 当然その一部っだったはずです 声が聞こえたとしても その声の主が見当たらなければ その人は多分そこには存在しない