My friend Elizabeth May is now an elected representative for the federal green party of Canada. She's had a lot of attention the last couple days, due to a twitter comment, sent from her blackberry, that she's glad she doesn't have wifi at home. The problem with such knee jerk reactions is that they're not based on science. This created all kinds of attention on twitter and the internet in general, forcing the green party to publish a policy position on the issue the next day. To summarize, her statement is based on the World Health Organization's statement that it could be a possible carcinogen. If the WHO lists electromagnetic fields (EMF) as a possible Class 2B human carcinogen, it falls under a long list of others, which we then can't ignore either. See this 10 year old list I've found which includes things like coffee, tea, aluminum, printer ink, as well as solar and ultraviolet radiation. There is no reason why you'd treat wifi any different than any of these other possible carcinogens, as wifi puts out less output than cell phone towers, and little more than a banana. See the XKCD radiation chart for some perspective.
While precaution is always good, having as much influence as a federal politician does, I think we need to think strategically and scientifically before banning items that potentially, maybe, under certain conditions, cause us harm. Not to mention items that save lives daily, and provide less risk than that which is naturally around us all day.
EDIT: 3:33PST: If you take a look at the WHO's electromagnetic fields section, which doesn't currently list wifi implicitly, it does include "broadcasting systems, microwave ovens, induction heating stoves, visual display units, television receivers, dielectric heaters for industrial use, radar installations, and medical devices and procedures." So if you're going to support the banning of wifi, you also need to support the demise of broadcast radio, and stop things like X-rays and CT scans, to name a few of the items affected by the above.
EDIT: 5:17pm PST: I'm adding a link to the WHO's Electromagnetic fields and public health - Base stations and wireless technologies - Fact sheet from 2006. You can read it for yourself, but the conclusion says:
Considering the very low exposure levels and research results collected to date, there is no convincing scientific evidence that the weak RF signals from base stations and wireless networks cause adverse health effects.