You're absolutely right that they should keep their hands where they we're entering the stall, I was talking about before entering the stall.
As for your question about using the aileron in a spin, when your wings are stalled you have that mushy sensation in the control colum..no? That's because they are no longer as effective. Remember in a spin one wing is more stalled than the other so by adding opposite aileron all you are doing is increasing the AOA on the "more" stalled wing. Hence worsening the situation.
I teach that students can use small amounts of aileron correction before they reach the pitch up phase of the stall, once they get there I just get them to make sure the plane is kept co-ordinated during the phase where they keep maintaining the pitch while they're increasing the back pressure.
An important thing to remember in the recovery is that when you've added full power you're going to receive a hell of alot of Torque thus you'll need quite a bit of right rudder correction (for a right hand prop)