How exactly would they watch for it? And even if they were watching for it, how would they go about confiscating it without opening millions of innocent pixy sticks--thus wasting money, manpower and public confidence?
The point is that complaining about the packaging of this candy is somewhat pointless given that the market it already full of products that can be used to disguise the contraband. Hell, if I were a coke dealer I'd just press my stuff into tablets and sell it as Vitamin C (no pun intended).