You can't reasonably kite just anywhere. The quality of the wind is important, if it goes over nearby land, usually the quality sucks. That means it has excessive gusts and lulls causing your kite to surge forward and stall repeatedly. If you are six miles offshore in Stiltsville from land, the land wind shadow seems to be far less a factor. The main restriction against kiting there is simple physics. You want wind that has been over clear water for as far as possible in short.
More about this common phenomena which has been responsible for a number of kiting fatalities by the way at
http://fksa.org/showthread.php?t=7879