[quartesixte]

To add to this: that "tell/sell/give to a foreigner" portion applies universally anywhere, and (the way I was taught), it can happen by proxy/passively.

Example: You put up on a whiteboard in a conference room an engineering drawing of a Air-to-Air missile's internals. When you leave the room, you forget the drawing on the board.

Later that day, somehow, a foreign visitor is walking around the office and peeks inside, and sees the whiteboard.

Congratulations, you just committed an ITAR violation.(Why? The apparent logic behind this rule is that spy agencies regularly employ people with photographic memories)

Another example: You take your phone that has your work email/chat on vacation to a foreign country. On arrival, your phone gets confiscated for "inspection" and then is handed back hours later. Bam. ITAR violation.

A nice side effect of this, by the way, is that you just leave all work stuff behind when you go on vacation. No pesky work-calls while chilling on the beaches of Portugal. Don't want to go breaking the law now, would we?