Weeeellll...My instinct would say that that to qualify as followers they have to consent, but more enthusiastic followers provide a greater benefit (I.e. a group of religious zealots who think you are the Second Coming will help a lot more than random thugs helping because you're paying the standard fee for the day), and it leaves them exhausted as if they had been doing hard labor for the time period of the ritual.
Mind control would work, but I imagine that the mind control breaking while in the midst of a ritual would be...Catastrophic.
