– When things go wrong on an airline flight, a picture is worth a thousand words — and a video can be worth even more.

That’s become evident over the past several months amid a string of viral videos showing passengers getting booted off flights, altercations between crew and passengers and the United Airlines passenger being dragged off a plane.

With smartphone cameras in the hands of nearly every passenger, episodes that once would have been bar-stool tales now become national news.

Do passengers have a right to whip out the phone and record whenever they want?

Airlines have sometimes prohibited fliers from recording on planes or at airports. Delta Air Lines says in its in-flight magazine: “If a crew member asks you not to use your camera/mobile device, follow his or her instructions.”

A recent filing with the U.S. Department of Transportation asked it to clarify the issue and state that airline passengers have a right to record to resolve disputes.

“Passengers face significant challenges in their efforts to hold airlines accountable for service they view as deficient or worse,” wrote Ben Edelman, a Harvard Business School associate professor and consumer advocate who filed a request for new rules. “Airlines and airline staff improperly attempt to block this market-based mechanism by banning recordings and purporting to ban recordings.”

It’s a gray area, pitting consumer rights against privacy rights, business owners’ interests and security concerns. The DOT says it’s reviewing Edelman’s filing.

Airlines’ policies on video recording and photography vary. The message Delta has had in its in-flight magazine for more than a year says: “You may use small cameras/mobile devices to take pictures on your flight. Always get consent from other passengers and crew members before including them.”

United Airlines’ website says: “Photographing or recording other customers or airline personnel without their express consent is prohibited.”

Enforcement is another issue. Passengers who shoot photos and video don’t always disclose that they’re filming.

American Airlines in May sent a memo to employees on “de-escalation” of passenger conflicts, outlining policies on passenger video recording. The memo says that “when videotaping infringes on the safety or security of a flight, we have the right to request that filming stop.”

Thomas Dickerson, an attorney and former judge who is the author of “Travel Law” on travelers’ rights, said it’s a bad idea to establish an unlimited right to record.

The captain “has almost unlimited power to tell people to behave or remove them from a plane,” he said. “They have to have that power to keep things under control.” Dickerson doubts the DOT will interfere with that power.