Stuart Green is the author of "Thirteen Ways to Steal a Bicycle: Theft Law in the Information Age," and a law professor at Rutgers Law School-Newark.

I’m always annoyed when I go to my local pharmacy to buy razor blades and have to ask a clerk to unlock the two-inch thick, bullet-proof case where they’re stored. You’d think I was asking to see the crown jewels. Still, it’s easy to see why stores take such measures. Gillette Fusion Power blades may give you a close shave, but an 8-pack sells for the extravagant price of $26.99. Without the locks, some people might be tempted to stick a pack in their pocket and walk out of the store.

Perhaps decisions about what products people steal are just as irrational and fashion-driven as decisions about what products people should buy.

On its face, a 50-ounce bottle of Tide detergent seems like a much less attractive object of theft. It’s big and bulky, and at a mere $10 a bottle, hardly seems worth the risk. So why the recent surge in klepto-Tide-mania?

The recent New York magazine article suggests that Tide thieves have engaged in a sophisticated form of analysis. Somehow, it’s claimed, they’ve all simultaneously determined that, compared to stealing other goods, stealing Tide offers greater benefits and lower costs.

The only problem with this theory is that it makes no sense. First, there’s no evidence that, compared to any number of other products, Tide is any easier to steal, any less likely to spoil, or any harder for the authorities to trace. In terms of benefits, stealing Tide should be no more attractive than stealing, say, Clorox bleach, Cascade dishwasher detergent, Similac baby formula or Jack Daniel's whiskey.

Second, the costs of stealing Tide are virtually indistinguishable from the costs associated with stealing other kinds of comparably valued goods. The amount of jail time for a theft reflects both the value of the thing stolen (the higher the price, the more time behind bars) and the means by which the theft is perpetrated (if you steal Tide by sticking a gun in someone’s face, you’re going to spend a lot more time in Sing Sing than if you merely took it off the shelf at the Shop Rite). The magazine article claims that Tide is an attractive target because its misappropriation involves simple “shoplifting,” rather than some more serious form of theft. But, in most jurisdictions, “shoplifting” is not a term with any real legal significance. Whether you steal a bottle of Tide from Wal-Mart, purloin it from another patron at the local laundromat, or pinch it from your next-door neighbor’s porch, you’re likely to face the same sentence.

Even if stealing Tide did reflect the high benefits and low costs claimed, it’s doubtful that most thieves would care anyway. Most thefts, like most crimes, are more impulsive, opportunistic and irrational than many legislatures and criminologists would like to think. People contemplating theft hardly ever take out their calculators before they steal (one exception may be insider traders). Rather, they see something they want, they have an opportunity to take it, and they do so.

So, what is it that explains the recent tidal wave of Tide thievery? My best guess is that decisions about what products people steal are just as irrational and fashion-driven as decisions about what people buy. The “must-have” brands of last season become the brands that one would not be caught dead with this season – think of Crocs. No one knows exactly why consumers make some brands popular and others not – for marketers, that is the Holy Grail. Similarly, no one knows exactly why thieves choose to steal certain products over others. Yet, as unlikely as it seems, Tide detergent has become the “must-steal” product of the season.