Sometimes the residents/patrons don't care about musical ability they just want to be entertained.
I believe it is the age old argument about musician or entertainer.
I wouldn't hire or go see the lip "syncer"(?) but maybe the residents enjoy the way he works the room, or banter between songs, or his smiling face.

Maybe he wasn't hired to specifically sing live but to entertain. You could go further midi vs live player, arranger vs live band. I mean its not opera at the Met.

We, as musicians want to chastise anyone that doesn't live up to our standards or our skill level. (Why would they hire them instead of me?) But the truth is there will always be jugglers, mimes, storytellers, comedians, karaoke and people that enjoy them.

As far as the other act always playing the same songs, tell them we're bored if you can't change things up we're gonna go with someone that can.
Of course really, if they don't have a contract they need no explanation at all to either act. Skip them and see if the residents miss them.

[This message has been edited by mikeathome1 (edited 08-16-2008).]