This one has a factory installed anti-theft system. There is a fuse box
under the hood at the front left side of the engine, while looking at the
auto from the front. Three of the fuses in this Nissan labelled box are for
the anti-theft system, so I would have to conclude that this was available
as a factory option. Whenever the battery was disconnected, the alarm would
have to be disabled with the wireless remote-control unit. My Ford Windstar
acted in the same manner, defaulting to the armed mode of the alarm.
The problem with the Nissan is that when this fellow's wife ran out on him
she took this remote control along with her.

Pete