I am with BEagle and propulike on this one. Let us not get involved in Flight Safety here. The bottom line is that in the confined space of an aircraft cabin, just as in a train, mobile phones can be a nuisance and intrusive.
You see it every day. On landing as soon as the seatbelt sign is off there is a rush to switch on the mobile phones. What is that important that it cannot wait until disembarked. It is as if there is a need for a phallic symbol to be clutched to the ear in a "look how important I am" gesture!
If there is a Flight Safety hazard it will be due to an increase in 'air rage'.
I understand it is possible to purchace 'jammers' that cause interference at short(ish) range on mobiles. They have been used with success on trains and coaches. Now there might be a Flight Safety hazard.........!