Since time has elapsed, is there a different/more efficient way to achieve this? I'm specifically concerned about doing this while temporarily offline. Also, it seems the cookie persists, so if you later scan a code and discard it, the form gets populated with an old number. Lastly, would it be possible to bypass the "confirm" page and just send the info directly back to the form (i.e. they could just rescan if the code was incorrect)?
I understand this is a really old thread, but I would be deeply grateful if you can provide any advice.