It seems to me that unless having a "wireless" allergy is legally classified as a real disability, then having wireless signals around don't discriminate people with disabilities since it's not legally acknowledged as a true disability.
But yeah, do a double blind test with something like what jgpaiva mentioned and see how many of them are liars. I'm not saying it's impossible, but it's hard to imagine there really is a problem, especially with a big enough group in one small area to complain about it. We're bombarded with signals and waves all day long, and have been since radio became widely available. Not to mention satellites and cell phones, etc.
Also, most wireless internet devices use 2.4Ghz frequency, which is also what microwaves and wireless telephones and other wireless home devices use. Oh yeah, and PINE NEEDLES emit a frequency of 2.4Ghz as well. So they'd have to remove all Pine trees from the area too.
I wonder if these people complain when they get too close to a tree or microwave.