I think the wet carpet will get impregnated with the copper as it leaches out of the PT bunks and be held against the aluminum hull.
This is theoretically possible, I have just never seen it in my years. I once had a customer bring his boat to me with this claim. But it turned out his battery had fallen over, and the acid ran along one of the ribs and ate a strip out of the bottom of the boat that happened to be over the bunk. The boat was totaled. Fortunately, he had insurance, and they covered it.
I currently have a 1994 boat that has PT floors, and with a piece of Tyvek between it and the boat stringers, with ZERO corrosion. In fact, that boat had the cleanest, driest subfloor I've ever seen! I think the PT fear is repeated often and exaggerated a bit. I'm using the Tyvek trick on my next build, but don't see a need to try using PT plywood. My current system works great, so I'm sticking with tried and true.
When I lived in Cape Canaveral, Florida, corrosion was a constant battle, so you had to rinse everything CONSTANTLY. The salt air even rusted cars terribly there.
Regardless of whether you use PT, white lumber or Cypress, Cedar or Redwood, this is a strong reason to use actual bunk carpet that dries quickly, not some house carpet that stays wet a long time. And if you fish in the salt, rinse, rinse. rinse. Your boat and bunk wood will thank you.