The Washington Post, New York Times, NBC News, MSNBC, NPR and the Associated Press all said on Monday that news employees aren’t permitted to speak to or to fundraise in behalf of political organizations. They were unaware of any employees who had violated these rules in the past year.

Fox appears to be different. Critics have frequently noted that its opinion hosts, and sometimes its news division, favor Republican candidates and have been especially friendly to Trump. By appearing at rallies or speaking at fundraising events, the network’s hosts and contributors risk making the connection to the party more than just a rhetorical one.

“I do think that this shows how blurred the lines are at Fox News, where the talent doesn’t neatly divide between news and advocacy,” said Bill Grueskin, a professor at the Columbia Journalism School. He added, “If a newsperson is being used to sell tickets, that’s a problem.”

In fact, Republican groups trade on the Fox News personalities’ prominence in their promotional literature for their fundraisers, sometimes using Fox News’s logo to help sell tickets.

Update: Fox emails to say, “A spokeswoman said the network has addressed the issue with its contributors and hosts, as well as third-party agents who book events.”