I’m a cool aunt. Or so I tell myself. It is this hubris that led to a $50 charge on my iTunes account, after I so willingly handed over my iPad mini to my young niece the other night. Parental controls! Don’t you know about parental controls? Well, I didn’t. (FYI, I called iTunes support the next morning and was able to get the money back through what Apple deems a one-time exception for an “accidental purchase.” Next time, the charge is on me. I still have no idea what could possibly cost $49.99 in the Angry Birds Go game.) Still, a bunch of parents out there who have more practice in this area are probably shaking their heads right now in painful agreement. For example, my AllThingsD boss Kara Swisher among them, whose son — who typically spent $20 a week on game purchases — once racked up $3,000 of charges in 15 minutes after one mobile game changed the mechanics of its in-app charges and he mistook the new method for part of the game.