Yes. Bullmastiffs are bred to overpower and subdue poachers and their dogs - a VERY dangerous breed of dog (I know, I have one).
2) Running lose, often >1 running lose?
Yes. Dog was on a leash, yet owner was physically (and more importantly psychologically) incapable of maintaining control of her dog.
3) Previous reports of aggression?
Not mentioned/ No.
4) Unrealistic view by owner on the aggressiveness of their dog (often despite #3 above)?
YES! In spades - even after a VIVID demonstration that she had NO control over her dog -as it MAULED another dog - she still maintains that it would all be OK if only she had a few seconds to sweet talk her dog and convince him to NOT destroy the greyhound. Delusional!
Every potential dog owner *must* read the complete history of whatever breed they’re thinking about getting.
Hopefully, most of them would be dissuaded by what could potentially happen, should ~they~ fail their dog.