I have read what seems like a hundred different threads about the iPhone's accuracy when using Find My iPhone. None addressed my specific issue.
I have noticed that, outside of an occasional delay locating and updating the iPhone 4s, it's typically pretty accurate. It places the phone right in the parking lot of the office, sometimes right on the building itself.
Today while showing someone how it works I noticed that it displayed the phone's location in a parking lot more than a mile away in a plaza. A plaza that we were not in that day. I refreshed it a few times and maybe 30 minutes later it correctly displayed the usual location.
What gives? What sort of factors affect the accuracy of Find My iPhone? Why would it so consistently show the correct location, then seemingly randomly show an incorrect location? Same building, same office, nice weather...nothing seems out of the ordinary.