The insurance industry is warning pickup drivers to watch their backs. Tailgate theft is surging. Tailgates have a rough life. They get rear-ended, backed into objects and dented by shifting cargo. That’s why thieves find a ready market for replacements, selling them on EBay and Craigslist. They are even valuable as scrap metal. Tailgates are being stolen from private vehicles, commercial vehicles and even vehicles parked on dealership lots, the National Insurance Crime Bureau said.