This bandwidth is free for the taking, as long as you abide by FCC regulations. The ISM band, for example, includes restrictions on output power and requires the use of spread-spectrum modulation. The UNII bands impose complex restrictions that regulate EIRP (equivalent isotropic radiated power). The FCC even regulates whether standard antenna connectors can be used on unlicensed devices. Companies must get FCC certification for all unlicensed radio products.
Still, consumers have relatively little protection. For example, it's legal for a company to sell a 2.4-GHz cordless phone that renders wireless LANs inoperable. And there are no dispute-resolution procedures to protect you if you install an unlicensed wireless connection and someone down the street installs another system that causes interference. In fact, the FCC has little power to enforce the rules, and consequently, individuals and organizations routinely violate FCC rules by using amplifiers and high-gain antennas to blast their signals louder and farther.
Enterprises, service providers, small businesses and home users all love unlicensed systems because you can buy them Monday and have them operational Tuesday. Vendors that sell unlicensed gear say they can count on one hand the number of cases in which interference problems couldn't be solved. Maybe so, but what will we do when everyone shows up at the wireless party?
And the Answer Is...