The aussie's have never walked, they always wait for the umpires decision. So it is a no brainer to me, Broad was we'll within his rights to stand his ground.
Front on showed no nick, but there was a fault with side on hotspot, snicko didnt show nothing agreed, but a feather would not register either.
The crease line is the umpires, his foot was on the line, that means out. If you are gonna say part of his might have been in, no one will ever be...