They are kind of like giftwraps before giftwraps became a thing. When you zap someone you encrypt the zap request note to the person you are zapping. Only the person who receives the zap can see who sent it. Not even the lightning node / service can see who sent it. It’s all end to end encrypted. 

 And they work at least on Damus and Amethyst 🤙 

 Interesting thanks 👍