Yep, this is my worry too. Need a loan? Need a driver's license? Want to apply for membership in our club? Want to enter this museum? Submitting a claim to our health insurance company? Want a visa to travel to our country? Put your finger on this scanner. You damn well better test negative.
What will happen when these cheap scans become a routine part of routine traffic stops?
Or border crossings?
I read last year that a team of Japanese scientists is well on the way to developing a highly accurate electronic nose, which can detect remarkably tiny amounts of drug residues in/on someone, with the wave of a wand like a metal detector. Expect drug prices to absolutely skyrocket, and whole countries to more or less dry up, when these become affordable and commonplace at border crossings.