From the article
The judge said that even if parents had given their children passwords, many parents were misled by Apple's presentation of these "freemium" games as free and that Apple didn't adequately inform consumers about the potential costs. Judge Davila has allowed the case to continue.
If it's disclosure of the app about the in-app purchase, then it's the developer fault. If the dad should sue anybody, he should sue the developer of the app. But then, if the dad was to sue the developer, he won't be able to sue for 'damage' of $5 MILLION! If you sue, sue big and sue someone that has the money.
Although annoying, iOS requires that you enter a password for EVERY purchased made in the App-store or in app since last year. I fail to see how it's Apple's fault when it has taken the right precaution against unauthorized purchases. The father gave his password to his kid and should expect the consequence of such action.
I wish Android has such password protection in the market and in-app but it doesn't. It's easier to buy from the Play store and in-app purchases then in iOS.
If my kids were to have an Android phone, I would download one of the App PW protection app and password protect the market and set the phone up so that any time the kids are playing a game, their phone goes into airplane mode. I'll also restrict access to apps I deem that they don't need. Plain and simple. If the parents can take the necessary precautions and don't, it's no one fault's but their own if their kids messed up.