[Porsche-O-Phile]

Maybe one of you guys can help me out here:

A friend of my wife brought her car over today, an '02 Ford Focus, because the alarm was giving her fits. I took a look at it and determined that the car had a Ford factory alarm (the brain was right up under the dash and easily accessible) and the kill switch had gone bad. Bypassed it and she was back in business.

However (here's the weird part):

She initially said she didn't mind if I simply removed the factory alarm in its entirety, but I opted not to because when I unplugged the computer/brain completely from its harness, the car would not start. This makes me wonder if as part of a "factory" alarm install (usually a dealer option) they don't flash the main computer for the car telling it "if you don't get such-and-such a signal (from the alarm computer), don't start". This would actually be a good thing from a security standpoint (a thief would otherwise just reach up under the dash, rip the alarm brain out and be underway in seconds) but I'm wondering if anyone knows for sure, in case she ever decides to have me remove it for her 100%.

Thanks in advance.