I am on "The One Plan" (all-you-can-eat data) with Three UK network. I used to be able to take my SIM card out of my iPhone and put it into the iPad, and it will continue to work. Now all I get is a message that says "Your SIM will only work in your phone" and then I get re-directed to their standard portal page, which tell you how to buy one of their iPad SIM's. I have an unlimited data phone plan, why should they care which device I use my SIM card in? I can simply tether my iPad to the iPhone to achieve the same thing, and overcome the ban. (A little bit inconvenient because it uses more battery). If I want to tether to my PC, the iPhone 5 is just as fast as the iPad3, but tethering is allowed on iPhone, not on iPad. This ban is ridiculous. I think the UK operators are getting smarter like their US counterparts, and are now trying to stop SIM swapping. Bad news for the UK users.