Assuming that they are true EMF meters (ie. something with a very high impedance 'probe', field mill etc.) and not some crank fake device, anyone moving around on a carpet or non conductive floor in the near vicinity could create significant static charge. Any handheld device will certainly not give any sort of meaningful reading, it would need to be properly designed, tripod mounted and without anyone in the vicinity,
I'm not going to speculate on what any change in electrostatic field reading might mean, but from TV programs I've caught while channel hopping, the limelight seeking individuals seem like a bunch of ****.