Can't argue with any of that sound logic. Although, I've found a few tricks to minimize those problems. Gorilla tape inside the doorjamb or hatchback to hold the wire tight and in the same safe place (not in the top edge of the weather striping, so rain doesn't follow it in), offers some protection for the wire.
GE clear silicon under the magnet is awesome for holding it in place, preventing moisture migration, as well as preventing scratches and dirt from getting under it. I admit, when I finally removed that installation a few years later, it did take several minuets longer than expected to work the thin edge of an old credit card under the lip of the mag mount and cut through the silicon bond. However, it left not a scratch or any sign of damage, once the little remaining silicon was rubbed of the paint with a soft rag.
