The airlines understand their vulnerability and try to protect them. An American Airlines spokesman told us that AA's flight attendant manual contains this section, all in caps: "In the case of unexpected turbulence, cease all duties and take immediate action to protect yourself."
Flight attendant Jane Doe said that makes sense to her.
"What good am I to my passengers if I have a broken neck?" she asked.
A note to white-knuckled fliers, who may sometimes feel like the plane is going to "break" during turbulence: according to pilot Charles Feldman, the aviation expert for KNX radio in Los Angeles: "You have a much better chance of having a space ship suck you out of your commercial jetliner and take you to another galaxy than your plane being broken up by turbulence."
He notes that modern commercial jetliners are built to withstand such punishment, and as MIT's Dr. John Hansman noted last summer, "It's exceptionally rare to have structural damage due to turbulence."
Feldman advises all fliers to buckle up any time they're seated -- yes, even if the ride is smooth and the seat belt sign is off. And he said even babies should be in appropriate seats that can be buckled, as well.
So does the FAA.
"The safest place for a child under 2 on an airplane is in a safety seat, not a parent's lap," an FAA spokesman said. "There is simply no way to hold onto a lap child if you hit severe turbulence."
However, the FAA continues to allow "lap children" (those under 2 years old) and there are no current plans to change that rule.
But, back to the grown-ups. Jane, our veteran flight attendant, said one of the most exasperating parts of her job is watching people get up and head to the lavatories, even when the seat belt sign is on. She adds that frequent fliers seem to be the worst culprits, and that may be because they've seen the seat belt sign come on many times before, and nothing bad happened.
And yes, sometimes nothing does happen, but that's the thing about turbulence -- it can erupt without warning. So, you have to be ready, especially for turbulence that causes the aircraft to move violently and erratically.
As flight attendant Jane said, "When the plane goes down, you go up. Simple as that."
This work is the opinion of the columnist and does not reflect the opinion of ABC News.
Rick Seaney is one of the country's leading experts on airfare, giving interviews and analysis to news organizations, including ABC News, the New York Times, the Wall Street Journal, Reuters, the Associated Press and Bloomberg. His Web site FareCompare.com offers consumers free, new-generation software, combined with expert insider tips to find the best airline ticket deal.