lol I understand how the process works
Here is a picture of a frame rail on a ford truck.
That doesnt look too spot welded up to me...I mean sure theres welds around, but the entire top/bottom is straight....no interference. I could ground to (for instance) the right frame rail and not hit a single weld the entire way. again, is an entire Beam of steel less resistant than the 1/0 return path.
again, im only challenging the theory....I think it boils down to what has the least resistance.