I think the reasons why some may suffer and not others is quite complex. I have been sensitive to EMF's for over year now and had my fillings replaced about 6 months ago. I still experience discomfort from EMF's though not quite as bad. I thinks that EMF's, depending on there strength, have a deleterious effect on the body anyway regardless of whether we have mercury amalgam fillings in or not. It does appear that EMF's can accelerate the release of mercury vapour from fillings as you pointed out. It has been suggested that other factors such as poor immune sysytem also have a part to play in why some suffer and not others. And mercury is immunotoxic.