A bit of background reading:
Quote: "Some level of electromagnetic interference to aircraft systems is theoretically possible not only from active radio transmitters (such as mobile phones, small walkie-talkies, or radio remote-controlled toys), but also from unintentional emitters (such as ordinary radio receivers, computers, and in fact virtually any nontrivial electronic device)."
http://en.wikipedia.org/wiki/Mobile_...c_interference
Here's a quote from when the Mythbusters looked into the mobile phone ban:
"While certainly not a rigorous scientific study, the Discovery Channel television program MythBusters examined the "myth" that mobile phones are banned aboard aircraft to force passengers to use the airline's inflight phones. They concluded that this is "busted." Their tests caused no interference to a small airplane's avionics, but did so to unshielded equipment. They concluded that interference could occur aboard an aircraft if the shielding was not working correctly."
YMMV,
D
Edit: I wonder.. is the reader a "nontrivial device"?