Go ahead, player. Abuse it.

You don't know the POWAH of the Dark Side...
The storyline irony of Stiff Neck, however, is this:
It makes Dwarven PCs the most corruptible race, which is NOT as Tolkien intended. In the actual books, if anybody screws up, it's humans that screw up first.
Dwarves usually shrug off corruption for the most part.
And elves are nigh untouchable.