In the case of people going their off spec to fill in correct group make up, we should still have the spec that you come in to raiding.  I know some may be upset because you prefer your main spec before your off spec, but if the person who does not have a good raid attendance and holds a main role in the raid group make up, we will have a talk about it. But  seeing as though we have basically most set up Ex. last week's naxx group, this shouldn't be that much of a problem.