Don't know if I saw this before though it looks like it has been around a while. The welded brake disk that started this reminds me of a story. My oldest son had an old $800 dollar Scirocco. One day I had been teaching the kids about cars and had him and his friend help with a front brake job. That night I got a call, the Scirocco was not far from home, and the front wheel had come off.
Apparently I wasn't a very good teacher, as I hadn't made sure they double checked the torque on the front wheels. Anyway I went out to help. The tire was Ok, one of the lug bolts bent or missing. The car had slid on the brake disk and ground it flat, not a huge amount of missing material, but much more than a scuff to the bottom of the disk.
As I mentioned this was a very cheap car on its last legs, and I didn't want to sink anymore money in it than I had to. My thoughts were the brakes would still be functional, but the rotor would be out of balance. I took my trusty Harbor Freight grinder and ground off an eyeballed equivalent section on the opposite side of the disk and called it good. It worked fine for the short life of the car after