User blog comment:Lia Schiffer/396: The Bite/@comment-1248963-20100323212841

Wrong, he did release in front of Barragan http://www.mangafox.com/manga/bleach/v43/c371/11.html

Why would he bother in gathering all the lieutenants to present them to his "water" zanpakuto and release it in front of them if he could go around and wordlessly releasing it in front of whoever he wanted to hypnotise? Quote from chapter 171, when Aizen first reveals KS true nature to Unohana "The initiation condition for the hypnosis is to show the enemy the release of Kyoka Suigetsu" not just releasing but that the enemy knows that the sword is releasing.