Why is it so hard to passively stalk my friends' locations?

A personal reflection on the lack of good tools for passively notifying friends when you're visiting their city. The author outlines two ideal scenarios — planned trip overlap detection and spontaneous proximity alerts — then explores why no good solution exists. Key obstacles include social awkwardness, privacy concerns, safety risks, and the absence of a decentralized, privacy-preserving implementation. Existing tools like Signal, WhatsApp, and FourSquare Swarm fall short. The author concludes by settling for manual social media posts and hoping something better emerges.