I have seen a few horses that were trained by entirely different methods to entirely different cues. No one else could do anything with the horse.
I wish there was a survey to tell everyone the average # of owners a horse has in his lifetime. =/
Ironically, I am the 3rd owner of all three of my current herd.
As a perspective, when I bought "Tyke" (15yo, QH/TWH, 1970-1998, RIP), all of the other 7 owners contacted me to see him. Go figure.