Nobody says RUS shouldn't be used at a sing.   But it should be made clear in advance that it will be used.   And some of us won't be there.

That book is far more pernicious than any other book--especially, as I noted, a book lovingly put together by a singer over a period of years. And I'd be surprised if someone who has sung for 40 years doesn't have such a compendium of songs he or she likes to sing. It doesn't sound as if RUS should be necessary in the situation described.

Even better is no book at all--but we realize that that is a problem for some singers.