IMHO, no, but I would also say that whether or not your audience will remain attentive depends on what they expect. Of course, some of us -i.e. me - have a better voice than guitar skills and so have the opposite problem of trying to inject some tunes into basically vocal sets. I have heard sets of tunes that were just as facinating as sets of vocals, but I think it had more to do with the choice of tunes as opposed to whether there were lyrics or not.
And Bert, I would be reluctant to admonish to NEVER put dance tunes in a set when dancing is not possible - but it certainly is a mean tease to do it!!
Cheers
PoohBear