A pastor once told me that they are short of basses in the choir and may need to hire singers for a performance. Now I've always hold to the principle of "Only Christians" when it comes to serving. Since I'm not the authority in charge, I really don't care about enforcing such spiritually educational principle on a second party. However, if they have that kind of money to hire a performance singer, I believe it is better if they use that money to hire a Sunday School teacher.
Of course, the sad thing is, those of us who are of little faith in America has come to depend on the principle of "the end justifies the mean" in one form or another.