So in a previous game in a store my Waiqar managed to proc Betrayal on a 3 x 3 unit of Spearmen with a Front Line Rune Golem...
Betrayal causes a unit to melee attack itself, ignoring all dice symbols apart from hits and having no re-rolls. The issue raised was did the Golem's Brutal ability proc, increasing the threat from 3. I felt it would as Brutal is not worded optionally with a 'may' and specifically increases Threat.
My opponent was happy to go with it, but the peanut gallery were not so sure and felt this was open for debate.
Was I wrong to thing Brutal applied?
(FWIW it ended up being a moot point as he rolled blanks - D'Oh!)