Actually, I've talked to many airline pilots now who assured me that even if I used my cellular phone and Bluetooth headset while playing The Sims and watching my GPS in any phase of flight, I wouldn't disrupt a thing, that the electronics-on-takeoff rule is more of the most archaic rules in all of air travel. Yes, AM and receivers give off very weak signals in the 500-1800 AM range, but they are far out of the range of air traffic frequencies for communication or navigation.
I would be more likely to believe the reason they want your electronic devices off and stowed is a matter of safety, as I will describe as soon as those of you terrified of flying turn away from your monitor or scroll past all the blue text, and I'll meet you on the other side.
During takeoff and landing, an airplane is going through a series of different changes of pressure and temperature in many, many different systems in many different places on the airplane. Should they need to set down and evacuate the aircraft, they want everything out of the way so as to increase your chances of exiting the aircraft safely. You'd be amazed at how much harder it is to get out of an airplane seat with the seat ahead of you reclining (even that two degrees they go back), your tray down and a laptop on the tray.
From 10,000 feet and higher it doesn't matter because you would have ample warning before any controlled emergency landing.
Just as a matter of interest, if you were to ever travel aboard Air Force One, for example, they have an office on board that is in constant use when away from Washington, D.C. During takeoff or landing, you might see someone standing at and using the cellular fax machine.
The reason you're not allowed to use cell phones on airplanes (except when on the ground, taxiing) is that you waste your company's bandwidth by using multiple towers, and at FL350 (35,000 feet) you are in the line of sight of a lot of cell towers. That is actually a Federal Communications Commission rule as opposed to anything safety-related. In fact, if you use that Airfone system that is on so many airplanes, you are using a cellular phone, although I don't know if it has its own towers, that being how it gets around the FCC regulations.
If cellular/AM/FM/Bluetooth/other electronic equipment really messed up planes on take-off and landing, they would have to restrict and/or prohibit the use of all radios, laptops, walkie-talkie type radios, TV's, cell phones, and other electronics at and around airports. Yet, if you watch the ground crews, they are all using radios, often in places where they would really cause problems if it was possible.
The information I give above is as I have been given by professionals in the industry. If you are in the industry or for a fact know differently from what I have posted, please rebut me. I am not claiming to be an expert in all of this by any means.
But I will say to go ahead and snap away, and don't ever feel bad about it. I promise you won't bring down your plane with a camera.