Yep, Mary. I agree with Killen. As you know, I often phrase differently when I sing, and I try to let folks know to listen to where I am going and then jump in on the chorus. As a singer, I also prefer that folks join on the chorus only, for the most part.
BTW, one could never tell that you are an unaccompanied singer when you and George perform. It is a wonderful thing to hear the two of you.