the incerts are from xperia pr team given in an interview with phone arena regarding unlocking the bootloader and the warranty problems
"For most issues/problems, unlocking the bootloader voids the warranty. Sony Mobile only honours the warranty if it is a known issue in that model/batch of phones or if it is an issue that clearly could not have been caused by flashing a different ROM. Because a new ROM can have a wide range of consequences (e.g., it can overheat the battery or change the voltage, which can damage other components), that basically means that only a small subset of issues are still covered by the warranty. Therefore, even when the phone is in warranty, the service centre usually has to do a very costly board swap in order to get the phone back to its original state before it can perform any repair. The end-user has to pay for that part of the repair.
We are proud of providing the unlock feature to the developer community. Previously, there was a large risk of bricking the phone when unlocking with third party software. Sony Mobile’s solution remove’s that risk. When we initially provided the unlock feature, it was presumed that only highly skilled developers and super-users would take advantage of it. From blogs and discussion boards, it was clear that the community understood the risks and that unlocking largely voided the warranty. It appears that less sophisticated users (despite all our warnings) might be using the feature, and are now surprised by the consequences."
