Well I didn't really search a lot for reposts, so sorry if it is one.
The exploit is simple - The Destro lock talent Nether Protection (30% less dmg from X school of magic that hit you in Nether Ward) is usable without having talent points in it. Just spec into Nether Ward without taking the 2 points in Nether Protection and try against a caster. I don't think a screenshot is required, but I can provide one if someone insists.