There was quite a lot of work done a few years ago - at Cardiff, I think - or maybe Bath - where they managed to re-programme an infusion pump using key presses on a mobile phone a few meters away. There's lots of anecdotal evidence and several labs / hospitals / research centres have managed to duplicate the problems and prove that phones do cause problems, particularly digital phones. They seem to be able to inject valid digital "words" onto the data bus of equipment which then produces a response from the microprocessor - and off you go !
