5" additional backing on each side is important

A customer recently brought a quilt top for longarming but included backing that was only 2-1/2 inches wider on 2 sides instead of 5 inches.  I took photos to show why there is a need for 5 inches.

In the first photo below you might think this is plenty of extra fabric.  In the second photo you can see the bed of the machine is actually 1-1/2 inches beyond the needle area.  If the backing is too short, what will happen most likely, when the machine hits the clamps holding the backing, the needle will break causing damage to the quilt top.

The third picture shows that I was able to still use the short backing by simply moving the design farther away from the edge.  But as a result, I had to begin the stitching by tying a knot within the quilt body, something I try to do outside the quilt body when there is plenty of extra backing to do it.