> so long as investors have been alerted about which social media will be used to disseminate such information.

They have been:

> Item 8.01. Other Events.

> Tesla Disclosure Channels To Disseminate Information

...

> For additional information, please follow Elon Musk’s and Tesla’s Twitter accounts: twitter.com/elonmusk and twitter.com/TeslaMotors

https://www.sec.gov/Archives/edgar/data/1318605/000119312513...

from the BBC piece here: https://www.bbc.com/news/business-45105674