Folk clubs sometimes try that kind of stuff with floor singers picked to make the guest look great. Of course it only works if the floor singers are good, and the guest really is great.
Thev opposite artistic trick to Edmuund Burke's can work also. Following something big and spectacular by something very small and simple. Sometimes performers do this with a final encore, and a big finale - just walk back on and sing an unaccompanied song. It can be shattering.
Kevin