And, frankly, the simple existence of turbulence?

It’s not like the pilots can see a giant messy region of air up ahead. Sometimes they’ll know the flight overall will be rough and can warn you but generally most times they tell you to fasten your seat belts some turbulence has already happened.

A plane the other day dove suddenly out of nowhere. Less recently a door plug blew off a plane and nobody was sucked out thanks to seatbelts. Before that, a flight departing Hawaii fell a few hundred feet without warning shortly after takeoff. These all happened very publicly and with widespread media coverage.

Frankly, if you fly a few times a year and never wear your belt you’ll probably be fine. But it takes zero effort and doesn’t need to be strapped particularly tight to be effective. There’s essentially zero reason not to wear it and it can save your life.

Sometimes you just have to use a little of your own intelligence.

You mean the seatbelt light that is sometimes on but mostly off?

There's some weird disconnect in this thread. People seem to be completely misinterpreting me at every step.

I agree with this. The seatbelt light is as anachronistic as the no-smoking light. They should just keep it on at all times. People obviously are still incorrectly interpreting "seatbelt light off" as "I should take my seatbelt off now."

The seatbelt sign tells you whether or not you are allowed to get up and move around. Unlike the no-smoking light it has actual informational content.