Remember seeing bookies chalking this up (in the blessed days when they still did such things) on opening shows on very isolated occasions many years ago, usually with unraced horses. Is it still a thing?
Seems very odd when thinking about it now.
No reason to now, Mighty Marine. Even if not knowing anything about the horse, bookies can just lay a price a little shorter than the exchanges without any worry. Because they themselves can back it on the exchanges for a guaranteed profit.