If anything I would expect a Garmin to actually underread. If it was sampling at like 2 seconds then it might join the "dots" as you run around the bends, therefore underreading. You should get a meter stick out and measure :P.
Haha, ure welcome to come measure :P I'm pretty sure the garmin was wrong though- there's no ways I was running at 9:10 pace, it might be just over 3, but not 250m over.
Yup, I'd trust the guys who marked the track over the GPS. Although I still think someone should measure it - I'd like to have something to blame my slow time on;-)
Well I don't have a meter stick, so maybe I'll just take a ruler ;)
GPS generally read about 6% extra on tracks. thats what google tells me :P
so then it would work out to be about 3.05km, so on another track I could've run a 9:47 :P