It is illegal to jam a cell phone's EM signals, and it isn't because of the jamming's effects on the specific phones, but because of the jammer's unauthorized t

It is illegal to jam a cell phone's EM signals, and it isn't because of the jamming's effects on the specific phones, but because of the jammer's unauthorized transmissions in regulated radio frequencies. The FCC takes their job fairly seriously, especially when someone makes a product that is designed to break their regulations. But, the FCC has no jurisdiction over sound.