The game company's side of things
There are some excellent posts here from the banker's side of things, and more good ones from a user's side of things. Not many look at the game company's side.
The fraudulent charges discussed here aren't so much kiddies using their parents' cards to buy an extra month of game time or a new account. Rather, it's organized companies set up overseas, in places like China, well beyond the reach of most law enforcement agencies in the West. These firms employ people to collect as much in-game currency as they can, then they sell that currency to players in exchange for real-world cash. This is referred to as "farming" gold, and the sale is often called real-money transfer, or RMT.
Random_player_1 is a WoW player. He's not especially good, so he decides to purchase some gold pieces (the currency in the game) from one of these RMT companies. He hands over his credit card info, and a few minutes later, a representative of the RMT firm shows up in game and hands him his gold. Random_player_1 uses that gold to buy new gear, which increases the power of his character and lets him do things that were too difficult before, and he's all happy.
Now, what happens to that credit card info? Well, without telling Random_player_1, that RMT firm uses his info to open a bunch of new accounts. Those accounts each get a free month, but require a credit card to activate. Each of those accounts is used to farm more gold (to be sold to other players), or to spam advertisements in the game (an offense that can get the account holder banned, which in this case would be our innocent, blissfully ignorant Random_player_1), or to do other nefarious deeds in the game. If the RMT company is nice, they'll cancel the trial accounts before the free month ends, but more likely, they'll let it roll over to a paid account, hoping to get another month or two of service from it before the card holder notices the extra charges, contacts Blizzard, then (when Blizzard refuses to refund the cash) disputes the charge with his bank.
You see where the problem here lies? It's not with Random_player_1, who didn't do anything illegal. He did something pointedly _foolish_ in trusting his info to the RMT firm, but it wasn't illegal. The fraud happened on the part of the RMT firm, which misused Random_player_1's credit card info. There's no clear evidence that Random_player_1 did or didn't authorize the charges, other than his word against that of Blizzard (note that there's no evidence of the RMT firm's involvement here either). Ultimately, the bank is left holding the bag. They have to refund the cash to the player, and as a result they end up fining Blizzard for excessive chargebacks, even though Blizzard had nothing to do with this whole mess and is as much of a victim as Random_player_1.