If someone prays for you and you don't want it you can just ask them to stop, without revealing you are an SS. You can simply tell them you do not care for their prayers if you notice any negative effects from them.
When people say to me "god bless" I laugh at them and say: No thank you, I bless myself with my own power, keep your god to yourself. Sometimes people look funny at me, especially hardcore xians, but then I just laugh again and give them a dismissive gesture.
Just like aldric said, we are unlike other people, we are strong and we have strong wills, or atleast we should have. When your will is strong enough some silly fools praying for you in church or to their "god" is just laughable, it doesn't affect you in the slightest.