fyi, "for official use only" or "fouo" is a slightly more than meaningless designation to shield stuff against FOIA inquiries. most of the stuff you'll find is pretty boring.
a little more: https://en.wikipedia.org/wiki/For_Official_Use_Only#United_S...
I worked for a government lab some time ago, and FOUO wasn't used to shield against FOIA. Indeed, OUO documents can be released to a FOIA request. It was more or less just the default because no one wants to get in trouble for not making things that are supposed to be marked.
What I've seen used as a shield against FOIA is the label, "DRAFT - For Discussion Purposes Only." This is meant to ivoke the "deliberative process" exemption.
+1. I don't think I ever saw a document marked UNCLASSIFIED// that was not marked UNCLASSIFIED//FOUO. I'm not convinced that there is such a thing as a document that should be marked unclassified that should not also be marked FOUO.
I'd imagine you could generalize that observation to any intentionally published work of the government. That's also my understanding of FOUO from when I needed to know: the agency I worked with thought of it as a magic word for "not meant for release" (in spirit, not legality).
