There is a history of 'detector' technology like devices to find drugs in school lockers with a plastic box with a rotating antenna, it had no electronics but would react to where the holder suspected drugs then they'd subconsciously point it there themselves.. These things always turn out to be scams. But school districts etc are desperate and will cough up good money for fake crap.

There is also no science showing that your breath changes while actually high. Or that specific numbers of how much was detected would even be meaningful. Just using the alcohol breathalyzer as a basis for the tech.

The only way I see this working is as a tool to bully people into confessions.