The person I know who did this is 5' 3", her husband is 6' 3", they bought a pair of matching mats. Maybe got a discount for buying two, I don't know. After a few years, they got a smaller tent and the size began to matter more. But I can think of all sorts of situations where you might want to reduce a mat in size. For instance, you might be shorter than the smallest mat, or the one you want might only be available in a large size. Or you might have a mat which has suffered an unsealable puncture or terminal baffle failure, you could then repurpose the remaining length as a torso pad, sit mat, child's mat or bed for your hike-a-dog.
