Dumbledore certainly didn't prepare himself in anyway when he grabbed the false locket out of the basin in the cave. Think about it. If you're going to hide something that important with the thought that it could fall into other's hands...wouldn't it be wiser to make it seem innocuous? An object that killed people when touched would gain the attention of the Ministry of Magic and probably assure its destruction.
So, innocuous looking but dangerous when attempting to destroy it. Probably another reason why Voldemort chose such revered artifacts as well. Doubt that many would have the guts to ruin the sole remaining possession of Ravenclaw...especially if it doesn't seem to do any harm!
Stephanie
In every man there is something wherein I may learn of him, and in that I am his pupil.--Ralph Waldo Emerson