I'm assuming you have the factory alarm? Aftermarket alarms often have accessory functions... that might be a better choice. My system takes about 2 seconds to resume (laptop in standby) and I find at least once a week I want to roll up my windows and really don't want the system to wake up and kinda wish I had put my bypass switch in a more accessible location. I'm wondering if you will see similar frustrations.
I could see situations where you unlock your truck to get a widget out of it and then lock it and walk away. Now your computer is running. Even 10 or 15 minutes like that and your battery will be weak for the next start.
Definitely not bashing your idea as I know people here have done similar things. Just giving my 2 cents.