Whose kidding who here. Lets face it half the time the dancers don't listen to the tune, only the beat driven by the bass player and the drummer. If you've got a good caller they should keep the crowd under control. If the caller has asked for some weird concoction they should know when the time has come to get everyone back together with, for instance, "It's lines together, forward and back". It also helps if you've got a band that can speed up, slow down and add bits on to make it all come right. Like a lot of life it has to be a team effort.
Our drummer also lets us know where we are in a tune with little rifts and runs, or, for instance the 'B' part might have more bass drum .