Stop Cell Phones Without Stopping Pacemakers...
If the manufacturers would just get together, they could easily come up with some sort of a "mute" system.
Basically, you have a small transmitter that broadcasts at a certain public frequency. Cellphones have a receiver that catches this signal, and automatically flip the cellphone to mute/vibrate. This way, when the person leaves the building, his/her phone will revert to the old function.
This could be extended to disable the phone's radio, or just individual components, such as cameras, video, etc., as well.
All it would take is the manufacturers getting together and coming up with a common protocol.
It'd be a hell of a lot better than jamming all signals outright.