> Similar patterns abound nationwide, suggesting that Karma's career was not unusual. Lex, a drug detection dog in Illinois, alerted for narcotics 93 percent of the time during roadside sniffs, but was wrong in more than 40 percent of cases. Sella, a drug detection dog in Florida, gave false alerts 53 percent of the time. Bono, a drug detection dog in Virginia, incorrectly indicated the presence of drugs 74 percent of the time.
I'm 100% convinced drug dogs are trained to "signal" falsely at certain things like a leash tug. It's all BS.
I should also add that dogs and many other animals really like pleasing people. So one doesn't even have to consciously train for outcomes like this. A famous example is Clever Hans, the horse that supposedly could read, do math, and answer questions like "If the eighth day of the month comes on a Tuesday, what is the date of the following Friday?" https://en.wikipedia.org/wiki/Clever_Hans