From memory (correct me if I am wrong) the Serbs used decoys extensively, NATO claimed to have destroyed a good proportion of the armour, APCs and Artillery that were in the Kosovo theatre, once the war was over and the Serbs pulled out we were treated to pictures of all that destroyed equipment moving intact across the boarder. There was embarrassment for NATO. There were a lot of tactical mistakes from NATO, yet there was a victory all the same.
Much of the reason for this was that NATO did not operate below 20,000ft due to the threat posed from manpads etc. and to be fair did not throw there whole effort in from day one.
My two cents from memory.