I have a bit of a theory about "ungenuine" horses. Just from noticing trends among those who die of heart attacks, quite a few seem to be well-known as rogues or at least needed headgear.
That’lldoboy, Detroit City, Challenger Du Luc (in retirement), Rooster Booster all had doubts about their attitude. I know there are more but cannot think of them quickly. Could it be that horses who save plenty for themselves are showing us that they feel something amiss?