Fraudulent listings are removed within hours and platforms do not share them, so marketplace fraud models learn from whatever one platform's takedown queue held. These are captured before takedown by the people who spotted them: contributors screenshot the full listing with price and seller area in frame, write a line on what made them suspicious and do not engage the seller; genuine listings and cropped screenshots are rejected, five per contributor at most. Capture is limited to 11 Southeast Asian countries, where commerce runs on Shopee, Lazada, Carousell and Facebook Marketplace and scam patterns differ from eBay or Craigslist fraud. The suspicion note is a free-text human label.