This IS NOT GOOD or amusing. One of the important lessons horses should learn is to wait on the rider and not anticipate. This is why I do not teach voice commands on the longe line and always wait a stride or two (or three) after the announcer asks for a gait change so the horse does not learn to 'que' off of the announcer.
Anticipating has ruined many good show horses from reiners to equitation horses. It is bad, bad, BAD to let them call the shots and learn routines or patterns unless that pattern is ALWAYS going to be used (like a barrel horse).
If I am riding a horse and he anticipates a maneuver, change of gaits or change of direction, I immediately change the program and make him do something completely different. It is also why I never follow one maneuver with another once I know the horse will make that transition correctly.
This is like backing every time you stop or doing a 180 degree rollback and jump right out of it. Horses soon start doing a transition on their own and 180 degree rollbacks become 150 degree partial rollbacks and the horse jumps out and takes off. Before a horse can learn to do that, I will do a rollback to the inside or do 1 1/2 revolutions, make a horse back up and THEN depart at a lope. In other words, I will set him up to listen to me and wait on me.
Horses learn to 'rush' fences. They learn to 'scotch' on their stops. [Trainers 'fence' horses running them all the way to a fence so they do not initiate a stop part way down their run-down in a reining pattern.] It is much easier to prevent a horse from getting too 'wise' than to fix it later. While it might be amusing to ride or watch one, a horse like those described is completely un-showable and a real pain in the butt.