Comment by palata
11 hours ago
> FWIW, I once went through an airport in my travels that took an infrared spectra of everyone’s water! They never said that, I recognized the equipment. I forget where, I was just impressed that the process was scientifically rigorous. That would immediately identify anything weird that was passed off as water.
Something like 10 years ago, I had my water checked in a specialised "bottle of water checker" equipment in Japan. I had to put my bottle there, it took a second and that was it. I have been wondering why this isn't more common ever since :-).
No idea if it was an "infrared spectra machine" of course.
Cynically, it's so they can sell you another bottle on the secure side. If they spend money to give themselves a working mechanism to distinguish water from not-water, they lose the ability to create retail demand.
I understand the idea, but it's not completely true: I empty my bottle before the security check, and fill it after in a fountain.