Yes you have. Take your cell phone and put it next to a radio or near your headset. Hear the beeps and bops? That is interference and it happens all the time. I can even tell when the ATC controller has a cell phone on.

Usually it is just a nuisance with noise in the headsets. However, a passenger with a cell phone who is seated near the ILS receivers, radio antenna, or near the magnetic compass sensors can cause a real problem -- especially if the device is malfunctioning and not operating on the proper frequencies.

Unlikely? Yes. If they want to change the law, I suggest they allow the use of these devices only during VFR conditions. Under IFR, I suggest people power down.