It’s an alluring idea for a police chief: You’ve got an area of town that’s a center for some sort of illicit behavior. What if you could just ban anyone who was arrested there from coming back for a year? Wouldn’t that solve the drug problem or the prostitution problem, or whatever else that’s hurting your city?

Charlotte, North Carolina, is the latest city to be tempted by the idea. The Charlotte-Mecklenburg Police Department is setting out to write an ordinance to fight prostitution by creating “exclusion zones.” If the department determined there was rising crime in an area, it could declare it such a zone. Anyone arrested there would be banned from returning for up to a year. If they were found not guilty or the charges were dismissed, they’d be allowed back.

When the Charlotte Observer’s report on the idea was published Tuesday, it lit up Twitter, with observers reacting with shock at the idea. But it’s not actually as novel as one might imagine. Charlotte itself had a prostitution-exclusion zone from 2005 to 2008, but chose not to renew it when the law expired. Portland, Oregon, had zones for prostitution and drugs from 1992 to 2007, when the mayor pushed to end them. But in 2011, the city reinstated an altered version. Cincinnati also used the zones for a while.

But there are some problems with the zones. “There are significant constitutional hurdles that must be addressed whenever the government decides to regulate movement in a public area,” the CMPD’s attorney bluntly noted in a memo to Charlotte’s city council over the proposed ordinance. Courts have been split, but some have argued the rules constitute a violation of the constitutional right to free association and to intrastate travel.

In Cincinnati, a woman who was arrested challenged the law after being excluded, because the order prevented her from visiting her grandchildren, who she was helping to raise. Although she was not convicted of the drug offense with which she was charged, the order held. She successfully challenged it. That’s likely not an unusual case: If people live in high-crime areas, they’re more likely to get mixed up in crime. Banning them simply banishes them from their homes—perhaps away from places where they have important social connections or can afford to live.

Nor is it clear that exclusion zones work all that effectively. During Charlotte’s first attempt, crime with prostitution zones dropped, but rose steeply in adjoining areas. Portland saw a similar experience. While residents initially applauded the zones as effective, the impact seemed to tail off over time, in part because officers simply quit arresting as many people.

The other obvious problem with setting up these zones is racial bias. It’s already well known that law enforcement for many offenses, including drugs, falls disproportionately on people of color. The problem is compounded when high-crime areas are also home to more people of color. When Portland ended zones in 2007, the mayor cited disproportionate targeting of blacks. African Americans who were arrested within zones were excluded at far higher rates than whites. In recent years, Cincinnati has pursued a total overhaul of its police methods. The Queen City has seen inequality rise more sharply over the last two decades than almost any other major city. School data show a city highly segregated by race. Charlotte is also already dealing with the fallout from the August mistrial of Randall Kerrick, a white police officer who shot and killed Jonathan Ferrell, an unarmed black man who was seeking assistance after wrecking his car. The city separately reached a $2.25 million settlement with Ferrell’s family.

Charlotte’s debate seems, in large part, to echo the broader debate over criminal justice in the U.S. As Kelefa Sanneh noted in The New Yorker last month, many of the tough-on-crime policies now under assault from reformers and Black Lives Matter activists were originally pushed by well-meaning black leaders. In Charlotte, one of the major proponents of exclusion zones is a black Democrat, Al Austin. Police Chief Kerr Putney is black, too.

Yet past experience—with both exclusion zones and tough-on-crime policies in general—is that even when they are able to overcome constitutional objections, they lead to more arrests for more people, and likely people of color. They are very effective at lengthening rap sheets, but since crime tends to just migrate when the zones are created, it’s less clear whether they do much to stop crime. And they draw resources away from other approaches that might help lower crime, from social programs to policing styles that deemphasize the volume of arrests, as Cincinnati has done.

Tempting though exclusion zones may appear, law-and-order approaches seem increasingly counterproductive and anachronistic today, especially since approaches like Cincinnati’s have shown such promising results.