I have worn the Dodge bra quite a bit and have seen no abrasion or wear, but have seen grit. The grit gathers around the bra parts in front of the wheel, but on the bottom side not next to the paint. I am sure grit can get under the paint from vehicles throwing it up, so I stay back from following other cars to closely as much a possible.
I take it off often to inspect, but have never found grit any place other than mentioned -- but sure it can get other places. To reduce chances of abrasion, before putting on the bra, I place 2" wide scotch tape on all corners and points of heavy contact to include hood, fascia, whatever looks like might trap grit and cause damage.
So far so good. Have 2 nicks without the bra and zero problems with the bra.