I noticed this a couple weeks ago when I needed to take something to the local Fedex Kinko’s (or Fedex Office or whatever it is they call it now). Fedex quotes their directions to one second precision! That’s ridiculous!
And not is their precision not right, but their accuracy was way off: this route took at least 9 minutes. Try it for yourself if you don’t believe me.
Fedex, look at the situation before you just tell your algorithm to round to the nearest second.