While I haven't used the AppStore myself, I'd expect the Buy process to take at least two user steps -- a good rule of thumb for an interface action with permanent effects, to guard against accidental clicks.
Maybe the user was expecting one more level of confirmation than the AppStore actually had?
Does your email program have a confirmation step after its "Send" button?
Confirmation steps, in practice, don't really help. After a few uses, people build up the muscle memory that "action, confirmation" is the action. Then the one time in a hundred they want to cancel, they don't realize until too late.
One approach to try would be, for any purchase over $5, make a "confirmation step" that looks like a restaurant bill, and require the user to sign it (with their finger). Perhaps "sign name next to a big number" would be enough to jar them.
But really, the solution is to make it undoable/refundable. No matter what barriers you put up, somebody will do it by mistake (guaranteed), and is going to want their money back. If I can return a $1000 jacket in real life, I should be able to return a $1000 no-op app.
This is the common behaviour in most ecommerce sites so is a reasonable assumption. When money is changing hands, verification should be standard practice.
By default, all iTunes store purchases are verified. Only if the user specifies that they don't want to have to confirm again does the store allow one-click purchasing. Though it would be nice if there were a big-ticket override, i.e. every item over $25 must be explicitly approved.
Please, read the article, examine the photo, do something before you comment. It clearly says in the review referenced that the guy in this case forgot that the buy confirmation was disabled (this is a preference).
The app store has one more level of confirmation- this guy just "forgot" that he had it turned off.
I did read the article but -- as I said in my comment -- I haven't used AppStore before, so I have no idea what "iclick" is or why something done on his laptop would affect his iPhone... I assume from your comment that it is the option to turn off confirmation?
If so, it strikes me as bad design that another user on another device can affect whether or not you get a buy confirmation on yours.
Maybe the user was expecting one more level of confirmation than the AppStore actually had?