I am not a specialist in either microwaves or human physiology, but what from having worked on AEW systems I know that EM radiation in a closed cage environment like an aircraft fuselage can create hot spots.
Mobile phones use frequencies that by available empyrical evidence can cause brain damage and cancer. Mobile phone towers are a recognised health risk, and engineers working near the receivers need to be careful not to get cooked.
So it is with a little horror I read the USATODAY.com - Cell phones test positive on AA flight article. I can imagine 20 phones in use in business/first class at the front, and one or more mini receivers at the tail of the plane, and 200 economy folk slow cooking in the middle. You might expect the thing to go 'ding' when it lands after an eight hour flight.
The idea is basically a good one, persuading the mobiles in the plane to talk to a local receiver rather than one of the other several hundred it can see from that altitude. Phones have always 'worked' on planes, by the way, it is the phone network that cannot cope with a few phones that can 'see' the entire network.
However there is a better use for this technology now. That is to make the receiver hand held so that a stewardess can 'detect' mobile phones that have been left on at takeoff. You simply walk through the aisles, make note of the number of the phones that connect and then announce that the owner of phone XXX please switch off, if they don't comply then send them a very expensive text message.