I would have to disagree from a very, very technical standpoint. Both have studbooks and although provisional registration is still available the Class I mares and Approved stallions are pretty much a closed set now. Both breeds are newer than say the Trakehner (which have been branded for years) or Hannoverian (which now requires six generations and the brand) but you can pick 'em out of a lineup.
Swedish Warmblood Registry Basics
I heard from my trainer that the Swedish studbook is going to be closed in the near future. She is very gung-ho about Hannoverians and Trakehners as 3-day event horses. (I am a T'bred person myself.)
This "vet" or "ex-vet" is clearly unhinged. Any old racetrack hot walker or any gypsy for that matter could tell you how to change the markings on a horse. Or "doctor" the teeth for that matter. And Rustoleum isn't how.
Hair dye works better, and isn't toxic. There were six different horses used in making "The Black Stallion", and they all needed a bit of "touch up" here and there. Of course, it's only a short-term fix.
I don't know much about designer warmbloods, except they cost a lot, and I don't see too many at the schooling-level local dressage shows. Some people think they're a "secret formula" for winning. Getting one cheap might seem a great deal, but the higher you go, the more paperwork you have to provide. Or maybe it's the same appeal that stolen art has for some people, where you can only enjoy it in secret.
A friend has an arab stallion, and is always afraid he'll be stolen because he's so friendly, and will gladly get in anyone's horse trailer. He associates horse trailers with fun things like dressage shows, and as a grey, he has no permanent distinctive markings except for a snip on his nose. She's still debating between getting him a lip tattoo or a biochip.