[Jet Jaguar]

If you have flown lately, people are constantly turning on their phones while in the air.

The bomb sniffers are working.

It makes sense to me to allow it. The the phones do not interfere with navigation systems on the aircraft.

[Drammach]

My main concern is that the terrorist no longer has to worry about smuggling his explosives on board in his shoes, or carry on luggage..
It could go in below-board luggage, or an accomplice could plant it on the planes interior or exterior in a seperate activity... ( plane maintenance, tire changes, clean-up, re-fueling, de-icing, etc.. )

All the "martyr" on board needs is a cell-phone to activate it.. and the correct phone # to call.

But, as Thackney pointed out, they don't take your phone, they just tell you not to use it..
Anyone inclined to suicide bombing probably isn't too concerned about rules on cell-phone use..