I can't find a news story about the incident I'm thinking of, but there are SEC regulations about the release of information to investors. You basically have to try to ensure that they all get the same data at the same time.
There was a case where material news was released on Twitter. It lead to SEC adjusting their regulation to allow for social media to be an official news outlet for material information so long as the company discloses that it is a source of information ahead of time.
One other point is that what you were referring to is not related to what OP was suggesting. You're talking about how the information is distributed. oP was referring to when it is distributed (too close to earnings).
I believe OP was wrong with regards to a restriction on when information can be released relative to earnings. Elon could have tweeted it a few days ago and it wouldn't have made a difference to the SEC in regards to the timing of the release.
Edit: here's an article referring to the change http://www.lexology.com/library/detail.aspx?g=f8c96f0e-832c-...