I don't believe for a second that anything being tweeted by billionaires, C*Os, and politicians is not approved by some marketing and/or social media department. It's not like people are required to tweet, they choose to tweet.

In the end Twitter is just the illusion of people talking to each other. It's all just to further their brand or to push their goals, not insight they give up for free. Sometimes someone slips up but this just results in even more carefully crafted tweets.