Originally Posted by
ube quilting
It would be wrong if the ruler edge was on a fold but in the demo it is just a single layer. This demo could be misleading to less experienced quilters.
It may be cut on the edge but it is definitely not a single layer of fabric. When she makes the straight cut (not on the bias) you can see the back side of the fabric layer underneath. Look at the .54 mins mark on the video.