The thing about toe in is that as soon as the pads wear in a bit, it disappears. It's true that calipers were "cold set" in bike shops all the time, but this was limited to low to mid level bikes. They wouldn't be ridden typically more than 30 miles a month or so, and it might be a year or more before the pads were worn enough for the toe in to be gone. By then they were either dry enough to not be so grabby, or it was a reasonable time for a tune up.
Campy record brakes (and Chorus etc) were never toed it, at least by anyone that knew what they were doing. People that had campy usually were enthusiasts who rode every day, and wore through the pads. If you were to bend the arms for the usual ~1/16" toe in, it'd be gone in a week. So it was more or less pissin in the wind. They didn't tend to squeeak anyway, at least with stock pads. Some people would put Matthausers salmon pads on campy brakes, and those could wail pretty badly.