I agree that common sense should prevail and that in the waves there is a different set of rules where by the water user on the wave has right of way.
If I'm about to leave the beach and there is someone coming in i'll wait for them to make the turn and head back out but in crowded situations you can be waiting there along time and if you've just spent the day frothing over getting on the water, given your boss the bird and broken the speed of sound to get to the beach then set up, launched and landed a few kites and finally got into position to get on the water it can be hard to be patient.
At the end of the day it's a big ocean and we all have a right to share it. Keep an eye out for your fellow water users give them some space and the bird if they piss you off too much and enjoy it.