Car alarm question

Just had installed an aftermarket remote keyless entry/alarm system for my 1988 Olds Ninety-Eight. I mainly wanted the keyless entry feature (all that fumbling for keys had me crazy), but the alarm was not that much more, so I went for the whole package. This alarm is a shock alarm, meaning that if the car is touched hard, the alarm will sound. I know from other people’s experience that loud noises/big trucks/sound systems that might cause a vibration may set off the alarm. I am wondering this question and did not see it addressed in the manual: if the alarm does sound when I am not around, it will stop in 3 minutes or so, I believe. But is the car still armed? Is there any harm to this situation? Worried because I could leave town in another vehicle, arm my car at home in the driveway, have a Mack truck pass by, and who knows what the result would be: no alarm coverage, dead battery? Thanks!

1 Try it! Arm and set off the alarm.

2 Wait until it stops in 3 minutes, or so.

3 Try it again! Try setting off the alarm without re-arming.

You might need to put a towel over horn/siren to help quiet it for the test.

1998 Olds 98? You spent money to put an alarm on a ten-year-old vehicle, worse than that, a ten-year-old Oldsmobile? Who wants to steal and Oldsmobile?

OK. You deserve what you get.

Your neighbors will hate you, because this thing will go off if the wind blows too hard. I hope you don’t live in my neighborhood.

And you did this just for keyless entry? I wish you luck.

Three minutes! Do you have any idea how long three minutes is? Someone is going to shoot your car.

Can you have this whole thing reversed and get your money back? If so, do it.