Ethereum co-founder Vitalik Buterin has expressed concern over X’s new geo-inference feature, arguing it poses a potential threat to user privacy despite its purported goal of transparency. The country labeling system aims to shed light on user origins for combating misinformation, but Buterin warns that this approach could backfire due to sophisticated methods of manipulating location data. He believes accounts could be easily faked to appear as if they are from specific countries, even leading to the emergence of political troll accounts seemingly originating from established nations within a short time span. Buterin advocates for an opt-in system and transparency regarding geo-inference, emphasizing the need for user control over their privacy while recognizing the inherent challenges in constructing an opt-out mechanism that protects users’ anonymity.