Why rely on a model?
20,000 phones are being sold an hour. Why not buy 200 phone's off 200 shelves and test them comprehensively at 0 mm, 1mm, 2mm, 3mm ..... The cost to volume sold is completely negligible and it is useful consumer information as 3 percent of the population is electrosensitive.
An estimated 30 million people suffer from Myalgic Encephalomyelitis (chronic fatigue) in the world and the average diagnosis takes seven years. Chronic health conditions are increasing exponentially. Healthy people aren't sensitive to environmental stimuli but unhealthy people are and the number of chronically unhealthy people grows by the day as livers strain under the stressors and weakening of modernity.
Turn your wifi off in your house at night and see if you sleep any better. Pretty simple anecdotal experiment. A house without the wifi on or excess electrical componentry on has a nicer feel. We did not evolve with this electromagnetic radiation and the cost of testing is negilible given the global population's growing exposure to it and something interesting may fall out of the research.
The risk of Apple having to make slight design modifications if research raises an issue is not a huge concern of mine. One hours phone sales should cover it and then they could further differentiate their products and raise prices.
How many electrical engineering schools are there in the world? Sounds like a great way for a university to get their staff free Iphones with a research grant.