I would think if the alarm is in valet mode, no sensors would trip the alarm. The alarm goes off even if the doors are unlocked, and locked in valet mode.
I looked all over the hood, and didn't find a hood sensor. I'll look again this weekend.
The hatch in back turns on a light when opened. I suspect that the alarm is tied into that, same as the front doors.
If the speaker is disconnected, there should be little battery drain even if the alarm goes off --just the timer circuit.
The OEM/ODM for the system is Code Alarm, now owned by Audiovox.