What kind of power are we talking about? Recognize that 2.4 ghz is essentially a line of site transmission, and does not penetrate through walls very effectively. Its also around the same frequency as your microwave oven. Those operate in the 1500-2000 watt range, but don't cause interference outside the house and are shielded with a simple faraday cage. Seems the commercial guys would be killing a lot of pigeons to provide sufficient power for free WiFi over large areas.

Is the sky really falling?

Brad