The best defense of apparation binding is that no one in their right mind would think the colleges actually do it. Like binding i-cant-believe-its-not-a-daemon just seems like a really braindead move for the colleges.Nah, but see, it's a reference to Mathilde's first title (Dusk Rider/Twilight Rider)
Besides, the Gold College calls the Dark Hounds Gehenna's Golden Hounds, so I don't think it's much of an issue.
Which is why no one suspects it's actually what's happening.