Locking Nuts v. FLanged Nuts

What Mil spec says they can only be used once? And is it because of what an engineer put on a drawing, or does the spec itself tell you not to reuse them? I do not have any specs in front of me, but I will when I'm at work Monday, and I'm going to let you know what MS-21044 and NASM-17830 says. So is McMaster-Carr lying to the world about re-usability?
McMaster-Carr
It's listed in our program requirements and limitations specs, not the supplier. McMaster Carr is one of our suppliers however.