All it takes is one trip through salt to permanently impact the cheap steel pipe GM uses for its brake lines. And if the car was never in salt, the new owner may be. This is a just say no moment. Nobody should be owning and/ or driving a ten-year-old GM sedan in the upper Midwest or northeast if avoidable. One can buy a 2011 Honda made in Ohio if made in USA is a key criteria.
Go look at ATIKOVI post on his low mileage GM sedan and the brake pipe going into the ABS. That is very, very normal, not an exception for GM sedans and the like.
My Wife's 2000 Bravada with 60k had a brake pipe fail because of corrosion at 60k miles. NO EXCUSE for that to happen. Thank God it happened during a weekday in a Panera parking lot. My Wife, like many other Americans, may not be so savvy on accident avoidance on a failed brake pipe. I replaced all the brake pipes in my Wife's Bravada with copper/ nickel brake pipe. It did not cost me much but was a royal pain in the dupa to do the job. SHAME ON GM FOR EXPLOITING ITS MOST LOYAL CUSTOMERs. THEY KNOW THEIR BRAKE PIPE STEEL IS BEYOND JUNK FOR ITS MIDWEST AND NORTHEAST CUSTOMERS- BUT THEY CARE LESS.