I'm another that cannot see what stall size has to do with whether or not a horse will cast itself--I too have seen a horse get cast in a very large shed...have seen them do it in the pasture--give them a large pasture & they're still likely to go & lay down next to the fence & then roll over into/against it.
krissy, people on here do not always take the side of the seller...sometimes it's the buyer, sometimes the seller...I'm guessing that you're judging by a thread or two of yours. Makes a difference if the buyer knows nothing about horses, if the seller deliberately lied....if the buyer knew there was a problem with the horse and bought that horse anyway and then comes on here & complains about it...all sorts of different scenarios and so all sorts of different possibilities when it comes to how people respond to a thread like this.
As far as equine vets....every state may have an equine vet, but that doesn't mean they are close enough to use for every call. Here we have vets that do know something about cattle but are by no means equine specialists....the nearest equine specialist is 100 miles from here, and there are many things that he doesn't/won't do--for those things the horse (and for that matter dogs, cats, whatever other animals--for certain specialized procedures almost all animals must go out of province) must go to the large animal hospital at the vet college in Saskatoon--a 7 hour drive from here.
I have to think that if a seller offered me the book "horses for dummies" I would be inclined to say no thank you, you likely need the book worse than I do, please keep it
The vets guide to Minis I'd accept politely--I don't have that one, though I do have other horse related vet books that are IMO better overall.