Sensors might need to be replaced because they are overly sensitive and always going off or if they are malfunctioning, a knowledgeable source said. Another said that area was particularly prone to false alarms because of birds landing on the fence-line and tripping the sensors.
There are instances when multiple sensors may be needed if false alarms is the issue. Anyone who has a clue about perimeter security knows that. Oh wait, we’re talking gubamint here, huh?