In the beginning, the kite invasion in our windsurfing area, it was like dogs and cats, then it quieted down a bit as we got to know each other as well as set some boundaries. We, us windsurfers, had to educate some kiters on wave etiquette, so things got better.
But then came the foils, kiters on foils, they crash a lot, and because they go down so fast, their kites often go down as well. Then they get pissed when we sail over their lines, when in most cases we'd have no choice, so then things started to get worse again. Just the thought of crashing into a kiter using a foil was seriously scary, you could loose a limb or even be decapitated by those things.
Then something happened that seemed to help, kiters on foils can't ride all the way to the inside on waves because it would get too shallow for their foils, so they would have to stay outside past the waves.
So now us windsurfers, at our spot, are hoping that all the kiters get foils, then us windsurfers will get all the waves.
Unintended consequences.