I'm pretty sure it's not EMI in the traditional sense but the strength of the output signal of the phone they're measuring.
It is not the transmission signal that is a problem. That is not what they are measuring. Transmission wattage is something that does not need to be measured. It is fixed based on the transmitter being used by the device.
All transmission/reception devices emit EM, above and beyond what they designed to do. How well that EM is controlled goes to the shielding of the device.
Whether the cell phone emissions are damaging to human cell tissue, or not, is the controversy.