Sealed for your protection

I noticed something odd. I work security at a supermarket a couple of times a month. Like most it has a small book section near the magazines. Seemed to be a bunch of thrillers and mysteries. Most were arranged in order of some un-named best seller list. One recent addition I noticed were some Spanish language selections. They also seemed to be thrillers. One thing that was different was that each of the Spanish language books was shrink wrapped. These were normal paperback books but they were each individually packaged. Only the Spanish language books were like this. Is this normal?