What's relevant isn't whether a technology or forensic discipline is good, just whether courts will accept it. Antonin Scalia (in)famously commented in one of

What's relevant isn't whether a technology or forensic discipline is good, just whether courts will accept it. Antonin Scalia (in)famously commented in one of the Supreme Court's dog-sniff 4th Amendment cases that obviously the police would want dogs that didn't produce false positive alerts, since they wouldn't want to waste their time searching where there were no drugs. The resulting caselaw sets up a situation where a dog can be wrong over half the time and still be used. The concept that "probable cause on four legs" would be used simply in order to get to search where they otherwise couldn't was apparently unthinkable.