Tanking with a DPS weapon?

[CurVG]

Lately, I've been seeing a lot of high-end Prot Warriors using a DPS weapon with their tanking gear and shield. I was curious on the viability of this setup and if there was some good reason for this. What do you think?

[Eravian]

Often it's because the defense rating on the tanking items is no longer an issue, and a dps weapon allows for better threat gen and dps output, particularly in Heroics. I know I'll use the Bone Warden's Splitter - Item - World of Warcraft over my Rimefang's Claw - Item - World of Warcraft sometimes, since it's more threat/dps and the survivability isn't even all that much less, because of the stamina and Agility on it.