Conspiracy theorists have always wondered why the hell the cell phone—a small device that gives off a tiny electromagnetic signal—is such a big deal to the FAA. Is it really possible that accidently keeping it and your Kindle and your iPad on during takeoff can cause some sort of technology shut-down in the cockpit? Is your decision to hit Airplane Mode the only thing keeping your pilot from being the next Sully?
Uh, no. It turns out there's really no technical need to turn them off at all. Flight crews just like an attentive passenger section during the safety briefing, and they don't like it when you annoy other passengers by making phone calls during your flight. That's literally it.
Everything in your life is a lie.