Yeah, you're crazy. Not easy to jump start when you can't get in the trunk without having to put power through the wires in the bumper. And reports that even if you jump start it, it's not drivable as soon as you remove the jump starter. And nothing says I don't know how to take care of my car like walking through a parking lot with a set of jumper cables and puppy dog eyes.
I have an A23 battery behind the tow hook cover to pop open the frunk. I carry a lithium iron phosphate jump starter in my frunk that I can use to jump start my 12v battery with, and if all else fails I carry a small 10mm wrench along with the jump starter to replace the 12v battery. There are stores all around me that sell group size 51R batteries, including a few within walking distance from work.
By the way, when my 12v battery dies I plan on opening it up as safely as I can to learn more about it.
P.S. replacing a 12v battery is easy and I've done it many times before on other vehicles. I've even replaced alternators, thermostats, brake lines, starter motor solenoids, and a bunch of other stuff in parking lots. Replacing an alternator on a Nissan 350z was not clean or easy job to do in the parking lot because you have to lift the car to get under it where the alternator is installed, and you have to disconnect a radiator hose with coolant in it to be able to remove a long alternator bolt.
P.P.S. I've limped 2 vehicles to a parking lot with my lithium iron phosphate jump starter. Both had dead alternators and discharged 12v batteries.