I have a friend who does PSG dressage . She will train her horse depending on his behavoir . If he gets it right she will often reward him by doing no more training ang going out hacking instead . If he gets it wrong she persists untill he gets it right. I have seen her go into the arena practice a short dressage test - then leave, the training over in only 5 minutes.
Good behavoir or the right position of the horse should be rewarded - often a rider or trainer will think I'm having a good session so I will keep it going which is a mistake.