I totally see your point about not wanting to go through formal protection training, but would you agree that the dogs should have to prove that they WILL bite (via a live bite or in a carefully and realistically staged scenario) before being bred? I don't think going through ever scenario in the book is necessary but for protection breeds, I think a breed-worthy dog should bite with confidence, in foreign surroundings, under threat.
I'd rather see a dog use good judgement in real world situations -- be willing to bite, but have the sense to know when the threat is over without having to carry through. I've been fortunate in being able to see Kharma do both, though, exactly as her breed has been bred to perform, in a real life situation. I don't, however, think she would take a trial seriously at all. I realize not too many have the opportunity to see their dogs do what they are bred to do, naturally.
I've never gotten to see her hunt jaguar, of course, but I've seen her hunt, and kill, and called her back from stalking coyotes -- she's been too smart to allow herself to be drawn within reach of the rest of the pack but she's REALLY wanted to catch one out on his own. I've seen her pack hunt with Shiva and/or Bimmer, and seen how they split up and work together when guarding me or working cattle. I've seen her deal with wild cattle, and I've seen her deal with human threats and her reactions to gunfire in real life situations, and that, for me, is the only truly conclusive testing. Anything else is speculation, but for the most part, educated speculation in the form of trials is what we have to extrapolate from to find out if the dog will react appropriately under threat.
Many of the Fila people would give me holy hell for socializing her as well as I have, so that she can accompany me just about anywhere, but what good is a guardian if you have to keep them locked away? And these are dogs who want to be with you, 24/7, so a good one will figure out what he or she needs to do to be able to go with you.
I'd place far more confidence in a dog treated the way Stafinois described that one that's kept locked away. Besides, what good does the dog do you in the kennel?