Very Interesting article. He covered it well. However, even if one runs the SPR their GPS will not give the distance as 42.195 km(marathon distance). One other thing to note, is all certified courses add what is called short course prevention factor. This is .1 of percent to the actual distance. Hence, a marathon could be long by 42 meters. This was put in place to make sure if a course needed to be checked for a record it would probably be upheld.
GPS is a device that will always be longer that the race distance. We have several posts on this topic here. There is more to it than using your GPS to see if you ran long.