It makes logical and aerodynamic sense NOT to use ailerons very close to the stall...We all know that ailerons change the AoA of the wings and so if you are happily flying at max AoA (say 17 degrees) on both wings, nicely balanced and you put an aileron input to the right, then the left wing AoA could exceed max AoA and the right wing could be below max AoA. In this instance the left wing will stall and the right wing won't. Using aileron to further try to pick up the left wing will exacerbate the situation and the roll will continue.
Doesn't happen very dramatically on a training aeroplane where the insides of the wings tend to stall before the outsides and you maintain aileron authority even into the stall but I imagine on something like an Extra with an asymetric wing the effect would be quite pronounced. Sometimes it helps get aeroplanes into a spin - one FI I knew used to spin the C150 by applying full power, full left rudder and full right aileron to ensure it entered the spin.