"with no loss of structural integrity."

I agree with you, as I said bikes are over-welded in the sense of having masses of filler. Still hard to know whether the strutural integrity has been affected or not without a more rigorous process. I draw the collective attention to that Nash Touring bike with the crappy welds we had pictures of a month or two ago, who know what one is messing with. What we do know is the welding didn't succeed in looking good and there may be other things about it no more successful.

I think the concern is that filing creates stress risers. You have this flow of metal that is joining the frame, like an oxbow in the river, and while there is a weld that could look like the filed down version that would be strong, one may be cutting across the grain in filing the metal. I don't know and would love to have some weld-tec guidance. I can try and post this on Miller site.