That is one bloody big dog, give it a black coat and it could be a bouncer on the door of a nightclub!
My dads mate is a big chap, possibly the strongest chap I've ever met (not Schwarzenegger big, but naturally strong and a former rugby player). He's had several rottweilers that he's raised from pups. I went around to his house once with my dad (a good several years ago) and his rottweiler stuck its head out through the garden gate and I can honestly say to this day that I have never seen a bigger dog in all my life, its head was twice the size of mine and it still wasnt fully grown.
Whilst we were there this dog was one of the softest and friendliest dogs I've ever met, but when my dads mate left the room the rottweiler didnt take its eyes off you, needless to say I didnt dare move an inch for fear of it killing me (this was at the time the rottweilers were getting bad press in the media - aka "devil dog").
My dads mate said that when its fully grown, if it went on a mission to harm someone it would be a struggle to restrain it...and the Boerboel in the 2nd pic on that thread makes that rottweiler look small!
Thankfully the dogs he has raised over the years have all been gentle giants and not once have they been aggressive to anyone, which Im confident is down to the way he raised them.
With regards to the Boerboel, I can't see how anyone could restrain an animal that big when fully grown and in a bad mood.
I think you were right to air your concerned opinion Chris, I for one wouldnt like to be on the recieving end of that dog if it suddenly decided it wanted to hurt me.