They put that there because there are may low class low trash customers that open packages and take what they want (i.e., shoplifting). I've seen this quite a bit in more urban/poorer areas, especially with immigrants (the only people I've witnessed stealing were all immigrants fresh off the boat). I even bought a Swiffer from Zellers only to get home to find someone had opened the package, taken the brush out, and then put back on the shelf.
I was at Dollarama the other day and probably half of the ziplock bag boxes had been ripped open and pilfered from.
As a result, I've started shopping in "better" areas of town.
Time to re-introduce beatings to teach shoplifters a lesson. You're a pretty sad individual if you're shoplifting from Dollarama...