Technically, even in the US a warranty is only void if it's caused by something the consumer did; a 1 year warranty for production defects can't be voided.

Although I think it's fair that the company not have to deal with a defect that is almost certainly caused by something you do to your device. Like, strawman, but early iPhones sometimes encountered issues while doing an untethered jailbreak, or people would install tweaks that were less than stable (even sometimes on relatives' or friends' phones), then they would walk into an Apple Store with weird behavior and expect the fix to be free. That shouldn't be covered by warranty.