Well, they say they won't, but they certainly will have the ability once they begin installing RFID (Radio Frequency Identification) chips in jeans and underwear next month, in order to more efficiently track their shipments of your mother's XXL boot-cuts.
But Artemis, you whine, rudely interrupting my subtle attempts at a yo-mama joke, I don't know what a Radio Friggin' Doohickey is. Why should I care? It's like a bar code, right? They've been using bar codes since the seventies, and nobody gives a crap about 'em. At this point, I'm ready to smack you in the face. First off, you interrupted me. That is not cool, my friend. Not cool. Secondly, no, RFID chips and bar codes are not the same thing. They do have one basic thing in common (both of them contain a certain amount of data, and when they're read, this data is sent to a "reading device," like a computer or cash register, which uses that information to do important things like figure out what it is you're attempting to buy or make sure your passport is the real deal), but the way they do their jobs is so different, it's like comparing Elmo (the bar code: sweet, if a little slow) with Oscar the fucking Grouch (the RFID chip: a slimy son of a bitch who'll cuss you out soon as he'll look at ya).
See, a bar code is a printed series of bars that form a code. (Gettit? That's why it's called a bar code.) When a magic wand is waved over this series of bars, elves appear and make the computer register the fact that you are adding the Deluxe Blu-Ray edition of All Dogs Go to Heaven to your pile of things to buy. The bar code must be visible to the scanner-wand, and the average furthest the bar code can be is about 12 inches. On the total opposite side of the tech spectrum, an RFID chip is a small (like, teeny-tiny) chip that is installed- sewn, implanted, etc.- in whatever it is the installer is trying to track. Not only do RFID chips not have to be visible in order to be read, but they also can be read at pretty amazing distances (one was read from a distance of 69 feet at DEFCON, and that was in 2005- just think about how much technology in general has improved since then!). They can even be read through wallets (if a criminal has the right equipment, they can bump into you, get close enough to your credit cards to scan the numbers and info off them, and use those numbers to purchase things online- and you won't even know about it until your statement comes at the end of the month, unless the credit card company decides to freeze your card) and cars (like the FasTrak®, which can be used to drive non-stop through toll plazas in San Fran- the FasTrak® is read by magical RFID-readers inside the toll booths, and suddenly they not only have a record of all your comings and goings through the toll plaza... they have a record of where you've been the entire month!).
If a Wal-Mart employee forgot to rip out or disable the RFID chip in your jeans (the latter of which is actually impossible- they can stop monitoring it, but unless it gets killed- more on that in a moment- the chip will never really be disabled), then all of a sudden Wal-Mart can see where your pants, and therefore you on the days you wear those pants, are going. They'll know where you eat lunch, what grocery store you shop at, that you're heading to Tony's apartment four nights a week.
My preferred method of killing an RFID chip is sticking that mofo in the microwave. Nuking that SOB for 30 seconds ought to do the trick. Leaves an arc of burnt metal, but whatever. You are no longer being tracked. Or even potentially tracked.