i have never heard of that option - maybe it is USA only ?
seems it was when this was written anyway
http://www.techworld.com/security/ho...y-now-3631955/
so you buy - on 1 click - but unless you enter the code within some preset allowed time, the purchase is cancelled ? is that how it works ?
I don't get how that can work with immediate consumption items like MP3 downloads or videos, when their strict rule is if you listened/watched some of it so you must pay. Unlike with books, there is no refund option once you have accessed the download.
checking your link, and the amazon uk help, the 2 step verify seems to be something you use only when signing in on an untrusted device, so if someone steals your already -signed -in tablet it is not a protection, unless you can remotely sign out ? it is one code per sign in not a code for each time you go through the checkout - unless I amreading it wrong.