I'm sorry if this is a repost, but I thought of it while on my Warrior.
Ok, so my Warrior is a blacksmith. I can make these keys that can unlock chests. People never think I can unlock the chest, since I'm a warrior. (Unless if there's a Rogue in the group, or possibly another blacksmith with the key)
Anyway, I wait until the instance is over and run back to the chest when everyone's gone. If you're lucky you might get a nice blue, or some cash!
This really only works with pugs though, since your guild should know if you're a BS or not. This also works for Rogues too if you have a high lockpicking.
Thanks for reading.