Here is the language of the rule, excerpted:
EQ102 Judging
SOUNDNESS. Unsoundness does not penalize a competitor unless it is sufficiently severe to impair the required performance. In such cases, the imposition of a penalty is at the judge’s discretion.
Does anyone know the history of why the rule is written this way?
I hate this rule. I am not currently an active USEF member, but I am going to find one who agrees with me and collaborate on writing a change proposal. I assume that, just like signs that say “Do not put children in the bear enclosure,” there is a reason the rule exists. I am certain that it is not because we all agree that a horse who trots into the ring with his head bobbing should be competing on this day.