That has meant that even though there's no "smoking gun" evidence of a problem, it can't be ruled out, either. One particular area of concern is GPS systems - one incident report noted a 30-degree error in the navigation systems heading when a passenger turned on a portable DVD player. But it's also worth noting that the studies were mostly conducted nearly a decade ago, and the average cell phone actually sends out a less-powerful signal now.
There are real safety concerns, but they have more to do with a plane suddenly braking during landing and a cell phone or laptop flying through the air.
40 Years of the Cell Phone: Photos
The other issue is social, rather than technological. While some want to keep connected all the time, there are passengers who appreciate that a flight - at least for a while - is a cell-phone-chatter-free space. And it's worth remembering that the ban on electronic devices isn't new. Back in the 1950s and 1960s using portable FM radios was banned because they interfered with communications. The change is not only the devices we carry, but how we use them and what we expect.