I've hit three groups in which membership is restricted but posts are readable and at some point there's a post that says something along the lines of "We've always been a public group, but we're getting spam so I'm putting us on restricted membership". Continued readability may (or may not) have once been an option in such instances.

All public Forever Knight groups I know about have now been entered into that form you link to.

As the old laptop can't take fancy new software, I'm now copy-pasting messages into Notepad and saving as text files. It's slow going, to put it mildly.

However, I have completely collected one Very Important List: fkwarleaders. All the backroom posts by the faction leaders in four wars. It's a restricted group; but, as I was a scribe in the last war, I was admitted to membership. One brand saved from the burning!