Wireless Technologies and the National Information Infrastructure.
Chapter 12 - Electromagnetic Interference and Wireless Devices:
Unanticipated Interactions Among Large, Complex Systems

A general issue in electromagnetic radiation is the unintended effects of radio waves. These involve compatibility problems that can, for the most part, be solved either by shielding devices, keeping radio waves away from people and sensitive equipment, or changing the modulation scheme emitting devices use. However, with widespread deployment of small radio devices with complex operating characteristics, it is possible that at some point there will be interference leading to a system failure. Because of the large number of devices, the variety of ways they are used, and the complexity of the possible interactions, it is unlikely that every combination can be tested and potential problems anticipated.

New technologies will continue to be introduced that cannot be tested in all real-world situations. A recent example: the operator's manual for European- model BMW automobiles advises owners not to use a digital (GSM) cellular telephone while driving the car, because it may interfere with the car's electrical system and lead to premature deployment of the airbags. While this particular problem is no doubt fixable, it is one indication of the kinds of surprises that may crop up from time to time as wireless telecommunications technologies play a larger role in a complex technological world.