This is true for some machines. It has to do with the orientation of the bobbin. It has been a few years since I was a LAQer so I can't remember the details. It was possible to do circle and curliques in all directions, but the stitching did not look as nice if the whole row was stitched in the 'wrong' direction. That may not have been the reason for the person in the quilt shop that started this discussion, but it is still true.
If you are free motion quilting on a home machine the orientation of the bobbin may determine if you can free motion quilt at all.
Debra B.