Well… I’m gonna say that it’s something that may be a problem. It depends on exactly what the horse has done in the starting gate to get itself barred. If it is a flipper, that may indeed be an issue you may be wise to avoid. And if they do get barred, that is often the reason why.
It means that when and if the horse becomes tense, upset, over something when in tight quarters, it HAS, in the past, flipped itself. That is , thrown itself over backwards. It takes a certain type of “crazy” for that to happen, and in order to get barred they usually have to do it more than once. Consider it a type of claustrophobia, it doesn’t just go away. You may well never attempt to load the horse in a starting gate again in it’s life, but there are other instances when a horse may well be keyed up and ready for action, yet can’t leave right away. A horse who still retains the urge to “sign off” and flip is still the same horse. Loading into a horse trailer is a much less trying ask than a starting gate at the track. Gate flippers may be just fine shippers, if the trailer does not trigger the same fear.
Less likely that the issue will manifest with a horse trailer (though it still might), more likely in a 3de starting box.
Or, the horse may be just fine, never a problem again. You just won’t know for sure. But then, you never do know in advance, for sure, one way or another.
Yes, I’ve had a family line of gate flippers. Not all of them were, some were lovely horses, very talented and smart. And fast. But the ones who were bad in the starting gate, I would not have sold as a riding horse prospect… Too dangerous. And the option of flipping or doing other completely uncalled for panicking behaviour was always a consideration for them, in tight restricted areas where claustrophobia would arise.
A gate flipper has an uncontrollable fear of tight spaces, where they can not be free to move. It’s a true phobia. They feel trapped, and the fear makes it so that they can not THINK rationally (as much as a horse can think rationally). Then they flip and hurt themselves, and thereby increase their fear. So it can be a hard situation to rectify. And may result in serious injury to both horse and/or rider.