And to keep people from trying to buy cigarettes while underage.
Eyes are magic. Pattern recognition that reaches down deep, maybe past the reptilian. Getting looked at can cause anxiety.
Maybe this adds to the appeal of masks.
it goes straight to the amygdala - the "lizard" or the "fight or flight" brain - see the brain scans in the link below for example. It is very short connection path from retina, something like right past the primary visual cortex, right beyond the last layers of simple/automatic pattern matching.
http://nautil.us/issue/39/sport/the-strange-brain-of-the-wor...
> Getting looked at can cause anxiety.
not surprisingly as it is usually the last thing one see before being attacked, so no wonder that amygdala starts to fire well before your conscious comes up with upper level decision whether there is any danger.
I'm uncertain if it prevents shoplifting, but it sure pisses off people like me who were browsing and prevents actual shopping.