"Important information
Please note that you may void the warranty of your device and/or any warranty from your operator if you unlock the boot loader. See your device's warranty statement for details. Additionally, due to the modified device software, Sony’s repair network will likely have to replace key components before it can properly test, repair and verify your device using our repair tools and software. Consequently, if Sony performs a warranty repair, Sony will likely charge you a significant service fee for the additional costs caused by your modification of the software."
Ahi explica claramente que te quedas sin garantia si desbloqeuas el bootloader.
DESPUES, explican el POR QUE de la eliminacion de la garantia (software....), pero te aseguro que te quedas sin garantia tan solo desbloqueandolo