How Accurate is the Garmin Forerunner 405?

I'm going to start including some routes from 2009.

Shortly after I got my Garmin Forerunner 405, I went to a nearby track for a run and to break in my new soccer cleats. I wore my new GPS watch, because I thought a run around a track would be a good test of how accurate the routes appear.

http://connect.garmin.com/player/1734500

1. On the map image on the Garmin site, select the "Hybrid" box. Zoom In.
2. Press the "Play" button

You can see that I:
- Ran 1.5 laps around the outside of the track.
Stopped at the bleachers to change from my running shoes to soccer cleats.
- Ran 2.5 laps around the grass football field, which is inside the track.
- Had to detour around the shotput cage at the NW corner of the football field.
- Started getting blisters from the cleats and walked across the football field back to the bleachers.
- Put my running shoes back on.
- Ran 0.5 lap back to the gate.
- Started walking home, while trying to figure out how to turn off the watch.

For another somewhat silly perspective on Forerunner accuracy, check out this Garmin blog post, which answers the question: When using a Garmin on a cruise ship does it measure the ship's movement or your movement if you run laps on deck?