I live in Japan and I've never heard of such a regulation, and my cell phones don't have such a feature. Actually, it's not exactly a hardware feature, it's ju

I live in Japan and I've never heard of such a regulation, and my cell phones don't have such a feature. Actually, it's not exactly a hardware feature, it's just an app. After the Tohoku Earthquake in March, many people started using early-warning apps. So yes, it's commonplace.