I'm pretty certain Inoda's special ability can block sounds. I mean, Kirito should have heard Asuna gagging on his cock, and she should have heard Inoda and Kirito talking, during her first blowjob (Inoda had agreed they'd stop if Kirito and Liz came back), but it didn't happen. I always assume the silhouettes and sounds are there for the viewer but are invisible and inaudible to anyone Inoda doesn't want to notice.
Then again, maybe everything is perfectly visible and audible, but Administrator is just editing everyone's memory on the fly so they don't notice.
