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.
Edit: here's an article referring to the change http://www.lexology.com/library/detail.aspx?g=f8c96f0e-832c-...
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.