I didn't see your first post, and have just started book 3. I think this supposed effect that wizards have on electrical items is going to be hard for the writer to write around today. Such a person couldn't function at all in a city today. Heck, he couldn't even start his car because of the electric ignition (which has been around since before Dresden Files came into existence. If you are basically a moving EMF field, phones don't work, cars won't work, lighting wherever you go would stop.
It's kindof like the movies - yeah, you know they didn't think it through when writing it, but you just have to pass it off and move forward.