What’s so maddening about this is is that it’s often done by people who SHOULD know better–horse people who don’t have any experience outside their specific discipline or who are preying on ignorant buyer’s stereotypes of the discipline.
Just like others have said above, the hunter-jumper person advertises the jumped-to-the-ground junior hunter as “a dressage prospect.” The dressage person advertises the crazy horse that dumped his owner that no one in the barn wants to get on as an “eventing prospect.” The eventer with a horse who runs away with his rider cross-country advertises the horse as a “fox-hunting prospect.”
And a horse that is marginally sound at the walk and trot, can’t steer or turn reliably enough in the right direction to be ridden in company in the arena gets advertised as a “trail riding prospect.”
I’ve even seen very hyperactive dogs advertised as “agility prospects.”