Whilst Beeper is making life even more difficult for Android users, I do think many people in here are missing the point about an iphone having to be used. Let's be clear about something, the article states an OLD iphone can be used, one that can be jailbroken. This therefore implies that as long as the iphone is able to power on and has working wifi, the old iphone can be in any state of disrepair, as long as it powers on, has working wifi and can be jailbroken because all that is needed if the iphones registration data. Technically the old iphone would not even need to have a battery just as long as it can power on via the charging cable attached to it. I have no doubt their are thousands upon thousands of old faulty iphones that cost less than $10 that could be used for such a purpose.
Doing it the way Beeper is suggesting, whilst awkward and cumbersome, is still way cheaper than having to buy a normal fully working iphone.