Nice analogy, you "forgot" to mention the part where you take the ATM with you and hand it to someone else. But... nice try anyway.
Actually it's more like you're sitting around one day, and 'lil toeheaded Timy comes up to you with his iPad and asks you to buy a game for him. It looks innocent enough. Just a bunch of singing animals you collect and raise, sorta like Pokemon. And hey, it's free. So you enter your password, download the app, then hand the iPad back to the kid. You think the password is enough, so you're not too worried about much of anything.
...completely unaware that after 5 minutes of playing, 'lil Timmy sees a pop up in his game saying he can get extra coins to buy more monsters if he presses here. Not thinking about anything besides getting more cool monsters to play with, Timmy starts hammering the buy button to get those coins. One month later, you've got an extra $300 charge on your credit card bill.
Then the state comes to take away 'lil Timmy, because a bunch of people on the internet are saying you're a terrible parent. Shouldn't have spared the rod, man. This is what happens when you don't pay enough attention to everything your kid does. Now 'lil Timmy is destined to a life of hardcore drugs and cheap, loose women because YOU. DIDN'T. CARE. ENOUGH.