Well, I bring BOTH Rise Up Singing and The Folksingers Wordbook! And I also bring songsheets to pass around. Perhaps it makes a difference if the group you sing with is a "song circle," where everyone takes turns singing something and everyone else sits there quietly and listens, or a "sing-a-long," where everyone sings together, assuming that they know the tune and have the words. There's also nothing at all wrong, IMHO, with the kind of session where there is a mixture of the two options. I enjoy hearing a song I don't know done by someone that does it well, and I also enjoy participating with a dozen people in something everyone knows...especially if the words are in front of them.

A steady diet of RUS is boring, especially if you've been singing out of the thing for twenty years. At the same time, I think it brings people into the group...and once they're singing, they too can mine the DT for fun things to suggest the next time around.