Hello, I only have one wolfdog, never trained to protect or to bite, but I can say my impressions on this.
Thanks god, I have never been in a really dangerous situation with my dog, but she feels very good how I feel about other people. So if a drunk guy tries to join me in a cafe (happends

) and I say, no, I do not want your company, but he still tries to keep the conversation or sit close to me - Brukne always comes out (she usually sleeps under the table in such cases) and shows the most terrible manifestation of her

She growls, shows her teeth, fluffs the hair all over her back and keeps the tail straight up. Usually people understand this kind of argument much better than my words... But she have never tried to bite anyone - only gently taking in her mouth a hand of the people she really loves (at the same time wagging her tail and looking in one's eyes).
Ah, and the brother of my girl, Waidila Girios dvasia, had a situation when a stranger hit his 17 years old mistress. The dog (not trained for defence or smth similar) bite stranger's leg just to stop him. The policemen were amazed about such a great deffender