Drug-sniffing dogs are often construed as infallible in court, but an experiment shows both how inaccurate and manipulatable by their handlers dogs can be. In a survey of traffic stops, drug alerts were only accurate 44% of the time; for Hispanic drivers, it was even rarer, 27%. This has profound implications for constitutional protections. The Supreme Court says that dog sniffs are not invasive enough to require the police to have a search warrant or probable cause. At the same time, however, a dog's alert (even a false one) is sufficient grounds for a full search of person and property.