I have a problem with using a phone SIM in my Sony Xperia Z tablet. I have a 3 Mobile 'One-Plan' phone SIM that allows tethering in a spare S3 mobile phone running as a hotspot, and I use my tablet tethered to that. When I place the SIM in the tablet I get the SIMblock message and a link that offers to charge me more for a grossly limited data per month tablet plan. How might I get around this ridiculous state of affairs? If I can tether, why not just let me use the chip as I see fit anyway?? This is not a tether blocking problem, the tethering works fine, it's a SIM transferability problem. I know the T&Cs are against this but the net effect will be the same so I might as well set it up for my convenience rather than theirs! Does it work by IMEI in which case I guess changing the IMEI would work, which might be illegal in some places (though I'm sure I could go to some country where it isn't, change the IMEI, and come back...) The weirdest thing is, I have an older 3 phone SIM (same plan) working in another identical tablet without any problems!