Students in America's larger schools sometimes feel like cattle. Now officials are starting to treat them that way.

The other day a Texas judge slapped a temporary restraining on the Northside Independent School District. The district had moved to kick Andrea Hernandez out of her high school, the John Jay Science and Engineering Academy, because she wouldn't wear an RFID tag.

RFID stands for Radio Frequency Identification. The USDA started providing RFID ear tags to cattlemen a few years ago, the better to implement its National Animal Identification System. That program's purpose is to track the movement of sick animals to contain the spread of disease.

This year the Northside district in San Antonio began issuing student ID tags with RFID chips embedded in them as part of a new Student Locator Project. About 4,200 students at John Jay and Anson Jones Middle School were issued such IDs through the pilot program. Each RFID-enabled ID has a bar code tied to the student's Social Security Number.

Some of the students objected, but none of them objected as much as Hernandez did. She handed out fliers and started a petition opposing the RFID tags. For this, and for declining to wear such a tag, she was threatened with expulsion from the school. The district has made it clear that other students had better fall in line, too. According to the Charlottesville, Va.-based Rutherford Institute, which is representing Hernandez, students who don't take part in the ID program will lose access to the cafeteria, the library, and extracurricular activities.

Why is the school taking such a hard line? Not for the sake of student safety—John Jay High already has 200 surveillance cameras. The real reason is money: Public schools receive funding based on a head count known as average daily attendance. The higher the head count, the more money the system gets.

Hence, Houston's Spring school district boasted two years ago that after introducing RFID-enabled student IDs, the system "has recovered $194,000 in Average Daily Attendance (ADA) funding that would have been lost if the district had not been able to verify the attendance of students who were at school but not in their classroom when attendance was taken."

Other school systems are following suit. Austin is using GPS technology to keep track of truancy-prone kids; so are Anaheim, Calif. and Baltimore, Md. An Illinois school district is using GPS to monitor children getting on and off the bus. In California, the Brittan Elementary School District spiked an RFID plan only after parents objected. Again, the purpose was fiscal: "The funding of schools is based on attendance," a district official said at the time. "If we are wrong for whatever reason, it means we are getting less money than we should be getting."

Well. School bureaucracies may benefit from bigger budgets, but students often do not. Since 1970 federal education spending per pupil has roughly tripled, even after adjusting for inflation. Scores have barely budged. Anyway, raw cost-benefit calculations leave out the variables that critics of this brave new world find so disturbing: the invasiveness, the creepy authoritarian vibe, and the impersonal, de-personalizing posture of monitoring enthusiasts.

In an education "Trend Report," AT&T—which sells RFID technology—gushes that RFID "helps retailers track merchandise" and "lets libraries manage their book collections… By affixing tags to such high-value assets as laptop computers and overhead projectors, schools can keep the devices secure…. By asking teachers to carry or wear [RFID] tags as badges, schools can automatically clock them in and out…. [AT&T's solution is] scalable enough to be used to track tens of thousands of assets." Merchandise, projectors, human beings—they're all just assets. Things.

Not all school monitoring programs are so impersonal. Some get very personal indeed. Students across the country have gotten in trouble for disrespectful but non-threatening posts on Twitter and Facebook—even when they made those posts from home and on their own time. One Illinois district paid hundreds of thousands of dollars to settle a lawsuit filed after parents learned school officials were using webcam-enabled laptop computers—issued by the district—to spy on students at home.

At least those families objected. Others apparently have not in Missouri, where the Parkway district has issued hundreds of fitness monitors to record elementary school pupils' heart rates, sleep patterns, calories burned, and so forth—all in the name of combating obesity. Teachers will be able to see the data to monitor pupils' progress. Two school systems in New York have started similar programs.

Even if Andrea Hernandez wins her case, it probably won't turn back this tide of creeping Big Brother-ism. After all, as Northside School District spokesman Pascual Gonzalez told Wired magazine, "the kids are used to being monitored." The remark—sad but true—lends credence to a sardonic bumper-sticker you may have seen. "School lasts 13 years," it reads, "because that's how long it takes to break a child's spirit."