When we develop aircraft systems, we have to pass both EMC emissions and susceptibility tests. The FAA are rightly over-cautious about allowing anything on-board that has not been tested for emissions. This is applied to test flights and limits the test equipment we can use, which can be a pain.
I doubt whether any electronic gadget not specifically marketed for aircraft has been tested, and therefore, no matter how low the emissions really are, they will not technically be certified for flight.
Of course, someone back in row 50 in economy is so far from the EE bay that their equipment is less likely to be a problem than someone in first class (or the cockpit).