[smokescreen]

It is entirely possible that some decidedly evil team would take some high powered lights, say a car headlamp unit or something, and partially cover the lens with an infrared filter. This would have the effect of the blasting the field with both visible and infrared light. This could screw up the sensors. Of course, none of this would be done intentionally. Said lights would be for special effects and would be tied into a flashing special effects light sequencer.

-smokescreen