However, I would think trust is a total non issue for a dog who would perform the same regardless of who is holding the leash. In that instance, my humble opinion would lead me to believe the dog is simply biting for the love of the game, rather than "to protect". IMO, when a dog strictly does it "for the love of the game", its too easy for lines to be muddled as far as when and where the game starts and ends.
E-Dog - 2012 WPBTCA National Championships
The time when screech owls and Bandogges howl and spirits walk and ghosts break up their graves.
Act I, Scene IV of William Shakespeare's "King Henry VI"