No surprises really, and this should also be reasonable evidence that the modern mobile devices are not that harmful to the plane’s systems:
In a study released on Thursday by two industry groups, the Airline Passenger Experience Association and the Consumer Electronics Association, as many as 30 percent of all passengers said they had accidentally left a device on during takeoff or landing. About 67 percent said they had never done this, always ensuring that their electronics were turned off. Four percent were unsure.
In another segment of the study, passengers were asked if they turn their devices to “off” when instructed to do so by the pilot. Although 59 percent of passengers said they do fully turn their electronics off, 21 percent said they often simply switch to “airplane mode,” which disables the main radios of a gadget. Five percent sometimes adhere to the rule. And others were either unsure or do not carry electronic devices on a plane.
via Many Air Passengers Never Turn Off Electronics, Survey Finds – NYTimes.com.