A Proximity Alert was the event that a Hovercraft was discovered by Sentinel. A loud shrill alarm would sound to alert the crew, in particular the ship's Captain, Operator, or On duty Redpill. In the event that the alarm was raised while crewmen where jacked into the Matrix the Hovercraft's Operator and all Human born crewmen would then be forced to do one of three things: call all jacked in crew members back to the Real World, activate the ship's Electromagnetic pulse destroying all machines in the area and killing all jacked in crew, or be forced to wait and hope that the ship is not detected. Many ship Captains would find fleeing or powering down a more effective way of survival than risk using shipboard weaponry.
Human Counter Measures[]
The only true counter measure was the use of a Electromagnetic pulse carried by all ships in the Zion fleet. Other shipboard weapons could be used but would take fatal amounts of time to be readied.
Sentinel Counter Measures[]
Sentinels do not have any known way of sneaking past a Hovercraft without triggering the alert. However they have developed the Sentinel Tow Bomb which could be used at range to destroy ships without being in range of the deadly Electromagnetic pulse. While the bomb would still be detected the crew would usually not have enough time to react and would be destroyed, killing all on board.