"Davis learned of the course error from runners who said their GPS trackers showed they had covered less than 26.2 miles."
GPS rules for runners
A) You never complain when you think a course is short to the RD. These runners got what they wanted. A nullified result.
B) If your GPS registers short, it does not mean the course was actually short. Trust the course certification.
C) RDs shouldn't investigate if runners complain about GPS mismatch. GPS only records 1 data point per second and truncates turns. If runner showed the overlay from 2015 and 2016, only then should they have investigated. There's data online from 2015 with 26.1 and 25.9. Will they nullify those results?
People complain about GPS registering short for legit courses all the time. Notice GPS is short when you run 1600 on the track. Are all tracks short?
Will runners be so anxious to verify the courses were short in the future?