I am sure some of you have come across this question before. I do the timing and race results on most of the courses I measure for Certification and on a new 5K and 20K ran this past week-end I had a couple of people come and comment that the 5K was actually 3.2 miles and the 20K was 12.6 miles. And the reason they know this is because they ran with a GPS strapped to their arm. My initial inclination was to tell them to not trust the fancy instrument but I am sure that someone who spent a couple of hundred dollars on the device would not like to hear that. Is there a good response to people who, I'm sure, will start asking this a little more often as time goes on. I want to have an answer that sounds like I know what I am talking about, rather than taking offense to their suggestion that my course is actually too long. Would appreciate any comments.