Sorry not grey listed I think it's caveat emptor status? Where it's still traded but basically wild west and most traders don't know that they are if they own shares, then the companies fixes their shady practices.
But yeah, tweets aren't accepted as public information as much as real PR through outlets. Or that's how it was maybe 4 years ago, don't know if it has changed. That's why I don't pay too much attention for FinTwit since it's mostly for rumors or news updates. But when I did follow it I saw a lot of companies get caveat emptor status when posting info via twitter. Specially during the Cannabis boom a year or so ago. They were just saying ANYTHING to get things moving. Was crazy!