128 ETFs have Tesla in them and 55 have it as a top 15% position. Those ETFs likely have rules based on the sort of drop we saw today.
It’s easy to speak personally about not being an active trader but a careless tweets like this have consequences and can hurt people. The only argument to be made is that Elon doesn’t understand the effects of a tweet like this but I think we all know he’s a pretty smart guy.