Originally Posted by
joe'smom
I would say so, as there is no ditch (lower area) to stitch in with a pressed open seam.
I wonder what the purpose is, of sewing directly on the stitching line of a pressed open seam in garment sewing? I don't see that you'd be engaging any fabric with the thread, but just sewing over thread.
An example is stitching shoulder seams to facings, so that the facing stays flat. If done neatly, the stitching is pretty much invisible.