The other thread has nothing to do with this thread! You have a multi world champion riding her retired champion without tack here. Gracefully. The horse is totally with her. That's different from the other thread and people training horses without tack. Isabell's riding here. Not training. Not training.
The side rein part of that other thread was just strange. Put a horse in side reins to make a frame until the rider can adjust to bareback? But a beginner on a horse with side reins cuz the horse will be in collected canter? Don't think so.
Y'all miss the point if you think that the other thread relates in any way to a world champion dressage rider riding her retired champion without tack. Y'all just miss the point.
This is an awesome video.