[kevin_thibedeau]

After 9/11 there was a notice that went out to not use the most restrictive portion markings, unless truly necessary, in the interest of promoting information sharing between silos. In particular the NOFORN being applied excessively, limiting sharing with foreign allies.

[warner25]

There are still periodic reminders about this but, to the parent's point, it's still the case that nobody gets fired for erring on the side of prudence. You might get a few stern words from someone senior to you, but won't get wrapped up in a criminal investigation.

What I've seen in busy headquarters, dealing with a mix of classified and unclassified material, is also something like decision fatigue. Like there are multiple required drop-down menu selections and free text fields for classification and caveats every time someone sends an email in Outlook, and most people are kind of guessing about what's really SECRET vs. CUI vs. whatever else, never mind caveats for specific allies and partners. So what prevails are simple rules-of-thumbs like "just send all email on SIPRNet, marked SECRET, but not NOFORN because that will piss off the Australian deputy commander" until someone more senior says otherwise.