Only if your travelling near the speed of light <img src="/images/graemlins/smirk.gif" alt="" />
If you are stationary or moving relatively slowly (less than say 700 mph), the propogational delay shouldn't be much of a factor. My GPS doesn't update fast enough to be accurate if I am moving much more than 100 mph anyways, certainly at the highest resolution, where by the time it updates I am already several hundred feet beyond the marker and off the screen already.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)