Susan,
I used to sing in Massachusetts where there are lots of singers who clearly didn't believe. Some of them have altered lyrics ready to go. Some of them weren't too bad, like, "Shepherds washed their socks by night" and so forth, but many of the songs concerning Jesus or the Holy Spirit were trashed in some way.
I also remember when the impromptu Christian Gospel Sing at the Old Songs Festival was crashed by people who wanted equal time for the Buddhists.
We said something like, "yes, by all means you may sing Buddhist songs, but please do it over there------>"
MD