I think that's more the Dane trait than having a true protection dog that you could send on someone- guarding is more their thing. I know Daisy is very defensive of our house. She has a huge bark and an intimidating size/presence. Recently she wouldn't let 2 repairmen in and I had to physically restrain her. Meanwhile, Gunnar let them in because I allowed them in, but he didn't take his eyes off them the entire time they were here. But I don't think the temperament of most Danes would fit into the PP training style, they are too laid back.
And I agree, if someone wants to come in my house or yard with a 110lb Dane and 90lb GSD, more power to them!
Dan, I used to have a huge collection of Great Dane Reporter magazines. I remember an article about a black dane (can't remember his name but I think it was Thunder) and his trainer, Tony something, who specialized in protection training. It was a great read. I wish I could remember the specifics because Thunder was quite the accomplished dog.
Incidentally, I've read another article elsewhere that a lot of protection trainers, military, police etc would not use danes, not because of their temperament, but because of the fact that all dogs jump when they bite their subject. A GSD, Rottie, Dobie are perfect size for their target (the arm) during their training, whereas a dane in full bite mode easily reaches the subjects neck or face. They found it too risky to use danes for this reason. That may not be the case for all trainers, obviously, but I found it an interesting perspective.
I know from previous experience that I'd rather not share, that two of my danes have risen to the occasion and not only threatened but backed that threat up against a violent person.
Since they were used as estate and chamber guardians in their earlier years, it would makes sense that some retain their protection capabilities. It was only a little over 100 years ago that they were banned from dog shows due to their aggression as well. Not that aggression equals protection but just saying that to show that they aren't always as soft as people think.
I do know a couple people that dabble in PP with their danes, but I've not seen them in action, only read their stories.