It isn't about me not being able to see them, but them not being able to see me

The dean's always been doubtful; he says a confession box won't stop them going back to a passing thuggish friar; after all I know who most of my parish are, even with a screen between us, and they know I know, and I know they know. What privacy is this? I think this is where the dean most shows his lack of subtlety. It isn't about me not being able to see them, but them not being able to see me - does he understand that?

S. Harvey, The western wind (2018), 52