if you can buy something at supermarkets or discount stores and want to keep it inside a bag for carrying,
you can get a transparent/semi-transparent vinyl (plastic?) bag.
(sometimes, you need to pay for it.)
but when you buy some goods at drugstores, the sales clerks almost always put them in a black/silver/tangerine/etc bag
and hand it to you.
the bag is the kind that no one can see through.
do they do this for the purpose of protecting customers' privacy??