Once again, for clarity, I'm not a doctor. But a critical care RN.
Its depends. Its VERY uncomfortable having the endotracheal tube and orogastric tube down your throat. One of the first things most patients do when conducting SAT's is attempt to pull them out. The patient is confused, doesn't know where they are, what all this stuff on them is, etc. We often put patients in restraints during SATs so they don't self-extubate.
I have taken care of patients where I have been able to stop all sedation and the patient was absolutely calm, responsive to yes and no questions and could tolerate it. However, if the plan is not to extubate, then you typically continue with light sedation for comfort.