Another thought I had.
If Sound choice wants to sue you if you have ANY of their songs, then simply remove ALL SC songs from your Songbooks in V4.20 with the Tools > Edit Songs and click the "Hide in Songbook" checkbox.
If you want the maximum security against SC, then remove ALL their songs from your computer. If you have no SC, their rep won't find any on your computer or at your show.
I know some of you may consider this extreme,
but it's nothing compared to a frivolous law suit! 