A lot of people into kink experience some shame and guilt about their fantasies when they are starting out. So it is important that the rejection not come across as judgmental. This goes hand in hand with holding out hope that the sub will find a better fit with someone else.

I knew one Domme who had a serious problem with a stalker. Also knew a switch who had 3 stalkers though it wasn't clear to me if it was kink or vanilla related. She warned me that one of them might pose a threat to me but nothing transpired.