For professors at Long Island University's Brooklyn campus, Labor Day weekend was anything but a celebration. On Saturday, all 400 members of the faculty union were told that their services were no longer required and that their positions, their health insurance and their campus email accounts were being cut off. Classes for the semester start Wednesday.

The university imposed a lockout, a labor tactic in which current employees are replaced by new employees. A lockout differs from a strike, in which a union opts not to work as a tactic to get a better contract. In this case, the faculty union and the administration have been engaged in negotiations and there was no strike.

William A. Herbert, executive director of the National Center for the Study of Collective Bargaining in Higher Education and the Professions, said he could not think of an instance when a college or university had used a lockout against its faculty members.

The university has two main campuses -- Post (on Long Island) and Brooklyn. LIU has had labor disputes in the past, including a weeklong strike in 2011 by faculty members at the Brooklyn campus.

The main issue in the dispute, according to the Long Island University Faculty Federation, the union, is inequity between the pay levels of faculty members at the two main LIU campuses. Currently, half of Brooklyn faculty members are paid less -- in many cases significantly less -- than their counterparts at Post, says the union, which is affiliated with the American Federation of Teachers. The university is also proposing benefit cuts, the union says. The union also says that tuition rates are the same at both campuses, as are faculty qualifications. The university says the union is asking for a contract LIU can't afford, and says that the university tries to limit expenses so it can limit tuition increases -- and the university says that the salary levels are the result of past contracts, and that LIU is willing to move toward closing the gaps.

But the unusual circumstance in Brooklyn isn't a faculty-administration labor dispute -- there are lots of those. Rather, it is the lockout tactic.

Faculty leaders at Long Island University and elsewhere say they are appalled by the tactic of locking out faculty members. They say they have real doubts about the ability of faculty members hired quickly to simply take over classes. And they say this is a tactic that can hardly build trust between professors and administrators.

Randi Weingarten, president of the American Federation of Teachers, issued a statement saying that the LIU administration "would rather act like a tough guy and bully its faculty than meet its academic obligation to its students and confront a moral obligation to not pay one set of educators less than another. It's contemptuous."

The University Faculty Senate, which represents professors at all LIU programs and is not part of the union (although many of its members are), issued a statement saying that the lockout is related to a series of policies undercutting the quality of education and the role of the faculty.

"The [Senate] further protests specific administrative actions taken over the last several months that contravene past practice and the idea of shared governance," the statement says. "These include: the cancellation of courses weeks earlier than usual without consulting or informing those most knowledgeable about the courses; the posting of outdated and unauthorized syllabi on Blackboard, presumably for replacement workers to use; the recruitment of unvetted workers to teach the fall courses on the Brooklyn campus; the reassignment of other LIU personnel to provide coverage in these classes," said the statement.

The statement also questioned how shared governance could exist after the administration "blocked access to the university and its website for half the membership" of the Senate, meaning "this governance body is rendered unable to function."

Individual faculty members are taking to social media to talk about what it's like to lose a middle-class salary and health insurance overnight.

"This is terrifying," wrote Emily Drabinski, associate professor and coordinator of library instruction at the university. "We talk a lot about privilege in my circles, and the way that privilege insulates people like me from encounters with raw, brutal power, how terrifying and total it is, how people in power can make the difference between living and dying in instants. This is one of those encounters with brute power and its capacity to overwhelm and kill you on a whim. I live a pretty privileged life; I walk about the world as someone who really belongs in it. The police really do want to protect my well-being and my property, and with each passing year of accumulated middle class wealth, the entire economic system seems invested in ensuring my leisure-class pursuits of marathoning and working toward medallion status on my preferred commercial airline. Until it doesn’t. It’s a different thing to know in your body what that means. I am learning a lot this weekend."

The university released a statement Monday that said it was trying to protect students. "LIU's first priority is our students," the statement said. "We maintain an unwavering commitment to ensure that students continue their studies without interruption and that tuition remains affordable. This has been demonstrated by the university capping annual tuition rate increases at 2 percent or less from 2014 through 2020, an unprecedented commitment. LIU is proud of its long history of mutually successful negotiations. The university expects to uphold this tradition as it negotiates in good faith toward a mutually fair and fiscally responsible situation. Negotiations are ongoing today."

A few days before the lockout, the university announced that the faculty union had to either accept the current offer from the administration or face the loss of faculty jobs. A statement from the university said this approach would assure continuity in courses.

"As the start date for fall 2016 semester approached, the university was compelled to set a course of action to guarantee that courses would begin as scheduled on Sept. 7," the statement said. "Historically, the faculty union has instituted a work stoppage on the first day of classes on several prior occasions, including in 2011. While acknowledging that faculty members maintain a legal right to strike, it must also be recognized that these work stoppages were designed to cause the most disruption and impact to the student learning experience."

Union officials have responded that far more disruption is likely with quickly hired instructors who don't know the history of various classes and their learning objectives.

A spokeswoman for LIU said the university was "eager" to have faculty members return to the classroom. But for now, she said, good replacements are going to teach. "In addition to a large group of administrators who currently teach, a qualified group of temporary faculty with advanced degrees and expertise have been hired to ensure a seamless start to the semester while negotiations continue in good faith," she said.

Kate Bronfenbrenner, director of labor education research at Cornell University, is an expert on lockouts. She said that while they hurt union members economically, they pose a great risk to the reputation of employers, especially in the education sector. "If you have faculty members showing up who want to teach," it "looks very bad" for the employer to be turning them away, she said.