And yet some high-profile impersonators have lingered on the platform for hours or even days, breaking Musk’s rules by not having “parody” in their username. The tweets are increasingly popular, increasing the danger to Twitter’s brand in the eyes of advertisers.

Let’s take a look at some of the accounts that are still active at the time of writing:

An account parodying Ohio Governor Mike Dewine has also managed to escape a ban, despite his ten hour old tweet with more than 2,000 retweets announcing the governor’s plan to “exterminate the people of Columbus.”

Just to be clear, Twitter is cracking some of the bills. While this article was being written, an account masquerading as Senator Chuck Grassley was suspended, though it took nearly a full day for one of his tweets to garner tens of thousands of likes. It was a similar situation with a fake Donald Trump account, which had multiple tweets with tens of thousands of likes and one with over 10,000 retweets, and nowhere flagged itself as a parody.

Still, it’s bad for Twitter that these tweets lasted so long, especially those from fake brands. As of now, the company relies on advertising as its main source of income. And advertisers have shown that they are not big fans of a platform that allows people to convincingly impersonate them. There have been several highly brand-insecure viral tweets – perhaps one of the most infamous was someone posing as pharmaceutical company Eli Lilly, announce that insulin was free.

The company’s official account later apologized that people were fooled by the fake. Both Eli Lilly and Lockheed Martin, who… had his own cheaterhave seen dramatic falls in their stock prices on Friday, though it’s impossible to say for sure whether the tweets were even partially responsible for that.

On Thursday, Musk reacted to someone talking about fake messages from Nintendo and President Joe Biden with two smiling emojis, as shown in this incredible compilation of imitators (most of whom have since been banned, per Twitter’s Policy). However, I doubt he smiles much today; Omnicom, one of the world’s largest advertising agencies with clients such as Apple, PepsiCo and McDonalds, has released a memo advising its clients to wait a while before advertising on Twitter.

Musk has since said that Twitter will “add a “parody” subscript to clarify this,” but it’s unclear whether accounts should mark themselves as parodies, or whether Twitter will make that decision itself.