Listen up, flyers: United Airlines said it will start removing passengers from flights who refuse to wear headphones while listening to content on their personal devices, and such behavior could lead to a permanent ban.

The airline revised its contract of carriage on Feb. 27 to include the new provision, which sits under the "refusal of transport" section that outlines the instances in which United can boot its passengers from flights.

According to the document, United reserves the right to refuse transport — on a permanent basis — to any passenger who listens to their entertainment on speaker.

It also states that any passenger who causes United "any loss, damage or expense of any kind," may be responsible for reimbursing the airline.

"We’ve always encouraged customers to use headphones when listening to audio content — and our Wi-Fi rules already remind customers to use headphones," United said in a statement. "With the expansion of Starlink, it seemed like a good time to make that even clearer by adding it to the contract of carriage."

Passengers who forgot their headphones at home can request a free pair on their flight, if they're available, according to United's in-flight entertainment information.

The move inspired a strong reaction online.

"One would think this is common sense and airlines would have in their rules," said one Reddit user. "Now let’s have the same rule for airline lounges."

Others complained that this has become increasingly common on flights, especially among those with small children.

"As a flight attendant; we have to tell people literally every flight," another person said on Reddit. "It makes our jobs harder when we’re stuck policing common courtesy instead of just focusing on service & safety."