Well it would be like gin or early tosen. They would be catching bodies because no one knew what they did. Even aizen only told because no one literally could escape his hypnosis and by them knowing it easier to manipulate because they are in constant fear of an illusion. Any captain or lieutenant are useless to hide their information because mayuri or anyone can learn what they do. Honestly only barrangan (espada 2) and book mark fullbring guy would had a much higher body count if no one said there abilities.