> It's the revolution that GSM brought: just take your SIM and move it to a different phone. No permission required. This is not really true: 1. SIM-lock is a

> It's the revolution that GSM brought: just take your SIM and move it to a different phone. No permission required. This is not really true: 1. SIM-lock is a thing, where providers prevent you from using the phone with another SIM (because they sold you the phone below cost and you're paying it back through your subscription cost) 2. IMEI lock is a thing too, unfortunately. The situation might be different now but in 2011/2012 it was near impossible to use a local SIM in your phone in Japan because phone providers wanted to sell you a phone with a SIM so you can't use your desired phone.