Battery relocated to trunk, inertia switch?

I'd say you have found it, Dion. the switch I mean. I was going to point out that there are other kinds of inertia swithes for other than auto use, but trying to engineer what force, etc this one is already "there.".

Good point. I was just looking for a cheap option that I could easily find, didn't even think about the fact that I could end up with something designed for a different application that didn't work well.

About all you'd have to do is mimic the mounting orientation in whatever it came out of

Yup, red button straight up.

I am going to wire it into the same relay circuit that the fob triggers to open the BR100. I was thinking about trying to mount it somewhere where I could reach it if it trips due to a bad bump or something, but for now I think I will just mount it in the trunk where I can easily reach it. If it because a nuisance, I will just unplug it and look for a different solution.