Disrupting cell phone systems is a bad idea.

1) Major medical devices in first responder vehicles use the cell network for telemetry.
2) Many fire suppression and burglar systems use the cell network for telemetry and control.
3) Many home medical devices use the cell network for telemetry and warning.
4) The interdiction or wide spread disruption of the cell network could have wide and varied secondary and tertiary effects.
5) Under FCC rules it is currently absolutely illegal to do even by law enforcement (um because of all those other spectrum users).

Finally without going broad spectrum high power it is really hard to do unless you have a deep penetration into the cell network already. Nobody I know is going to admit that even if it is pretty much true with the extensions to CALEA.