TC (technical correctness) -speak may note that 'interference' trouble-they've-been-causing is a 2-way street.
So the cell towers could beam rays that disable Clearwire.

Curious this, that the Clearwire downbeat forecast comes out the same day as this NYTimes item in Business:
F.C.C. Bars the Use of Airwaves for a Broadband Plan, By EDWARD WYATT, February 14, 2012

WASHINGTON — A proposed wireless broadband network that would provide voice and Internet service using airwaves once reserved for satellite-telephone transmissions should be shelved because it interferes with GPS technology, the Federal Communications Commission said Tuesday. ...

Interference of LightSquared’s signals with GPS systems is a tricky issue for the F.C.C., telecommunications experts say, because the interference appears not to be the fault of LightSquared. The most commonly used GPS receivers tend to pick up signals from outside of the segment of spectrum designated for GPS.

Because the satellite-telephone segment of airwaves, used by LightSquared, is next to the GPS band on the electromagnetic spectrum, GPS devices will frequently hear those extraneous transmissions. [n.b.: Strictly said: "Unrefined GPS devices 'overhear' or 'eavesdrop' outside their proper assigned channel."]

The F.C.C. could have told GPS users and systems manufacturers that they were at fault for letting their devices stray into nearby airwaves, but that would mean overhauling an industry now in widespread use.

Jeff Carlisle, LightSquared’s executive vice president for regulatory affairs and public policy, wrote on the company’s blog [n.b., How to Source-Influence NYTimes Reportage] this week that the GPS industry had apparently become “too big to fail,” seeking protection from the federal government ....