Shay, I have spent my entire adult life with danes, and I will tell you I think Sasha behaved like most danes do when confronted with someone entering their home without being invited. If she were a loose cannon, your friend would be missing a limb (what with that 2000 psi bite danes have ). She was simply giving a warning. Your friend will probably never make that mistake again.
As for the friend, NO she hasn't done that again...