It is, but people are terrible about it anyway. At a minimum, it is a field day for social engineering attacks because you can learn to speak in the languages / abstractions of that specific organization which automatically leads to trust-building.
From what I’ve read, those with clearances that hear something outside of a secure area are obligated to report it immediately.
He then told me about a limitation with the SR-71 Blackbird (Apparently the panels of the body expand at high speed, so they have to be designed in a way where they have gaps and are leaky on the ground, until they reach sufficient speed.)
He said solving this problem would be a big deal. Then he wrote the word, “Aurora” on a napkin and immediately crumpled it.