Note that the "rule of silence" (combined with the habit of writing documentation like longform essays) is also one factor that makes unix-like systems newbie-unfriendly. (Famous example: trying to exit vi)
I think the rule makes sense within the specific constraints *nix programs are usually expected to work in (two output channels with no structure except the one informally defined by the program and the convention that the output should be human- and machine-readable at the same time) but I don't see it as a general rule if better ways to filter the output are available.
> Note that the "rule of silence" (combined with the habit of writing documentation like longform essays) is also one factor that makes unix-like systems newbie-unfriendly. (Famous example: trying to exit vi)
$ man foo
*scroll to the end with the EXAMPLES section*