What does Warwick Schiller say about horses that swap leads due to fear or stress rather than training deficiency?

Warwick Schiller's perspective on spontaneous lead swapping — horses that swap leads without being asked, particularly in corners, at specific points in the arena, or when other horses are present — emphasizes investigating the nervous system component before assuming the problem is purely a training deficiency. Schiller distinguishes between a horse that swaps leads because it is unbalanced or undertrained and a horse that swaps leads because it is anxious. An unbalanced horse swaps because the wrong lead is physically uncomfortable and the horse is seeking the more comfortable lead for its direction of travel. An anxious horse may swap for a different reason — it is in a heightened nervous system state that produces inconsistent physical responses, and the swap is a symptom of the activation rather than of an imbalance. His observation is that horses which swap leads in specific, consistent locations — a particular corner, near a gate, at one end of the arena — are often responding to a location-specific anxiety trigger rather than to a balance issue. The same horse may never swap in a different location or on a different day, and the training approaches that address balance deficiency do not resolve an anxiety-driven swap because they are addressing the wrong cause. For these horses, Schiller's approach is to address the nervous system state and the location-specific anxiety rather than drilling the lead or working on collection in the problem area. This might mean approaching the problem area from different directions, doing quieter work near the trigger location before any lope work there, and using the relationship and confidence tools he advocates to reduce the horse's overall baseline anxiety rather than specifically correcting the swap.