someone mentioned cracking the frunk open and leaving it. I know in my 993 theres a light that goes on and will drain the battery if its open(is there one i the 991?). you may want to disconnect the battery as well(assuming a trickle charger wont do you any good with power out)

 

Not necessary on the 991. The frunk light will turn off in about 12 minutes.

 

Sessionstu, if you can, please try to use a proper jack pad with center bolt.

 

Why not remove the battery altogether? It's no cure all but at least it would be a quick and easy way to prevent any electrical shorts from destroying the car.