Man, if I saw someone doing this (below) on a newly-painted frame, I would find a better bike shop.



Filing a chamfer like that will cause a line of rust to appear where the cup meets the face, and the rust will likely propagate under the paint, eventually causing the paint to fail and flake off.

The whole concept of facing a painted frame is flawed. It's almost never necessary, and it causes harm if the frame later gets a Phil Wood or most any other cartridge BB

Even if the paint is thick, it doesn't affect bearing ajustment unless the paint is thick on one side, like a drip or run. Any competent painter can make the paint film be uniform all the way around, so facing after painting is not necessary. Facing should be done before painting, and only before.

But facing by itself isn't as bad as what the guy is doing with the file in the pic above, that's malpractice.