Many of you youngsters think this is a new TSA thing and are you wrong. No one worried too much about electronic devices in carry-on baggage until the 1989 bombing of Pan Am Flight 103 over Lockerbie, Scotland. The device that destroyed that plane—and killed 270 people—turned out to have been hidden inside a boom box.
After this incident, Congress briefly considered banning electronic devices in the cabin. Instead, the FAA asked airlines and airports to exercise more scrutiny over cell phones, radios, alarm clocks, computers, and other electronics. As a result, many travelers were asked to turn on their laptop computers at screening checkpoints, to prove that they functioned normally. (Some airports made powering up a computer mandatory; others required it only for travelers who were afraid to send their computers through the X-ray machine.) Laptops with dead batteries were sometimes taken to a special room and plugged in. By 1993, the process had become enough of a hassle that one company released a program called "Airport Shut Down"; it put your computer to sleep—rather than turning it off completely—in advance of the screening.
So taking out a laptop for x-ray screening is childs play when compared what some of us elders had to go through 20 years ago.