> At the time of posting, I didn't know about any embargo. My contact had told me there was no embargo, and her contact had told her the same thing.

If you're not a party to an embargo, and no one told you an embargo even exists... you should not follow the embargo. In fact, you should maybe even consider leaking basic details or challenging the embargo if you are in this situation. In your situation, they had lost information asymmetry before the news got to you. I don't know where people got the idea that unrelated third parties have to follow embargos.

Embargos are not about keeping secrets, they are about the game theory of coordinated disclosure.