In regards to medical care, patients absolutely are allowed to pick what they want and to decline care, why should dentistry be any different? Ever heard of walking out of a hospital or ER AMA (against medical advice)? In other words, you don't have to take pills or get an MRI or any other treatment if you don't want to, even if they would benefit your health according to the medical doctor. Why should a patient be forced to get an xray in a dentist's office that they can't afford or they don't want if they're willing to sign that they're aware of the risks of refusal and still wish to refuse. You don't have to see them as a patient if you don't want to, but you don't get to force treatment.