I definitely prefer to have mine cut. The tearing will distort the fabric. I don't go by how it has been cut when I begin to do my rotary cutting for a project, anyway. I always fold my fabric in half, putting selvedges together and letting the fabric hang down. I shift the selvedges back and forth slightly until the hanging fold is completely flat (no ripples at all). Then I lay the fabric down, with the fold at the bottom, and using the fold line as my guide for the bottom edge of my plexiglass rule, I cut a new edge, from the fold up to the selvedges. This is how I was shown when I first started quilting. Hope it makes sense.