Celebrities, professional athletes, and other high-profile Twitter users are once again being verified by the social media platform and they don't know why their blue check marks reappeared — nor do they seem too happy about it.

Twitter removed the blue marks last week from accounts that don't pay a monthly fee. But the check marks mysteriously returned for many highly followed accounts over the weekend, leading some prominent users to disavow what's become a divisive symbol of Elon Musk's erratic changes to the platform.

The account belonging to the Auschwitz Memorial, which has 1.5 million followers and regularly tweets out photos and names of Holocaust victims, tweeted on Sunday, that after two days of no checkmark “our account got the blue tick back,” but said it was “obliged to clarify that the Memorial never subscribed and paid for the Twitter Blue as it might be implied.”

Other high-profile accounts with more than 1 million followers — ranging from Massachusetts Institute of Technology to Bette Midler, gymnast Simone Biles Owens, writer Neil Gaiman, and rapper Lil Nas X —took to Twitter to make it clear they didn't pay to get their blue check back.

“On my soul, i didn't pay for twitter blue, u will feel my wrath tesla man!” wrote the rapper who has 8 million followers. Added Gaiman, who has 3 million followers, "What a sad, muddled place this has become.”

Midler posted on Twitter on Sunday: “Yes, Elon gave me back my blue check but I didn't pay for it. Does that make me a good guy or a bad guy? I'm so confused.” But by Monday, there was no sign she had a blue check.

On Twitter, the blue check icon appears on accounts next to text that says, “subscribed to Twitter Blue and verified their phone number." Since last week, blue check marks also appeared on profiles of dead public figures, including author and chef Anthony Bourdain, who died in 2018; the actor Chadwick Boseman, who died in 2020; and the journalist Jamal Khashoggi, who was assassinated in 2018.

Also read: Twitter blue tick: Here’s how to retain verified checkmark

Under the original blue-check system, Twitter had roughly 4,00,000 verified users, including Hollywood actors, star athletes, journalists, human rights activists, and public agencies. In the past, the checks meant that Twitter had verified that users were who they said they were, as a method to prevent impersonation and the spread of misinformation.

But now anyone can buy a Twitter Blue subscription starting at $8 a month. It no longer means the user is verified — other than confirming a phone number — but promises a number of features, including the ability to have more people see their tweets.

Legal experts said Twitter doling out subscriptions to people and institutions that didn't want them and implying that they paid for it could run afoul of the federal Lanham Act, which prohibits false advertising and other regulations.

“Particularly when you click on the blue checkmark that says this user has subscribed to Twitter Blue.' If you are just giving out blue checks to certain accounts and it didn't say that, it would probably not be as big a deal because of the verification that they had previously, it just meant that they were somewhat notable,” said Alejandra Caraballo, an instructor at the Cyberlaw Clinic at Harvard Law School's Berkman Klein Center for Internet and Society.

But the fact that it does say the account is subscribed to Twitter Blue — especially if they have been outspoken that they haven't subscribed — can create a sense of “false endorsement,” she added, “that they are purchasing a product that they did not purchase and therefore the celebrity or person is endorsing this product.” That said, a false endorsement lawsuit would be limited to “actual damages” the person suffered as a result, Caraballo added.

Also read: Twitter blue tick: Here’s what you should know

“My guess is the most common thing is that if someone really is upset about this, they could send a cease-and-desist letter to get Twitter to take it down,” she said.

Musk has pushed for the premium service as a way to increase revenue and upend what he called a “lords and peasants system" that he believes gave too many people an undeserved status symbol for free. But only a fraction of users — and very few of those who had the blue checks before — are buying the service.

An inability to sell subscriptions or find other ways of making money could present problems for Musk, who bought Twitter for $44 billion last year and has struggled to keep advertisers — its main source of revenue — from fleeing the platform.