How do you know when join-up has genuinely occurred?

Distinguishing genuine join-up from a horse that has simply slowed down from fatigue or is approaching out of curiosity without the full social engagement that join-up represents requires reading specific behavioral markers that indicate the horse has genuinely shifted its assessment of the trainer from threat to trusted companion. The most reliable marker is the following behavior that characterizes genuine join-up — a horse that has truly joined up will maintain its position at the trainer's shoulder without any leading rope or encouragement, adjusting its pace automatically when the trainer speeds up or slows down and turning when the trainer turns, mirroring the trainer's movement the way a companion horse would mirror a herd leader. A horse following out of curiosity will approach and investigate but will not maintain the committed following behavior, stopping when the trainer moves away or drifting off when something else captures its attention. The quality of the horse's demeanor during genuine join-up also distinguishes it from other states: the horse that has joined up shows a soft, attentive quality — ears mobile and oriented toward the trainer, eyes soft and blinking, muscles loose rather than braced, breathing normal — that is distinct from the fixed, high-alert quality of a horse approaching cautiously while still in threat-assessment mode. The horse's response to the trainer reaching toward it after join-up also reveals whether the join-up was genuine: a horse that has truly joined up will typically stand and accept the approach of the trainer's hand rather than flinching away, because the social engagement of genuine join-up includes a level of physical trust that the approach of a known companion rather than a threatening stranger produces. Monty Roberts and other join-up practitioners consistently describe genuine join-up as having a qualitatively different feeling from what precedes it — a shift in the horse's entire energy and presence that is recognizable even to observers watching from the fence.