We've had multiple guild members hacked over the last year. That means stress, losing weeks of game time, having items/gold possibly not reimbursed, and in the worst case: permanent loss of the account or characters.
Go and buy the Blizzard Authenticator from The cost is $6.50 + shipping and will be the best $10-$15 you've ever spent (I spend that on coffee in a few days...) given how much we all play this game. I hate seeing any of our guild members go through the ordeal of trying to recover their account/characters, and they undoubtedly hate it a lot more. Don't be one of them.
At the brink of danger I stand. Clad in armour, shield and sword in hand.