Private gun sales are banned from most social media platforms, including Facebook, but a new Wall Street Journal story shows just how difficult it can be to proactively enforce the ban, given the creative ways that users have found to get around the edict.

According to the WSJ, would-be gun sellers are now posting pictures of stickers for sale alongside a gun company logo. Interested buyers are encouraged to contact the seller for more info, and that’s when the talk can turn from stickers to sidearms.

One seller in Amory, Miss., posted the logo for Glock Ges.m.b.H., an Austrian maker of semiautomatic handguns, describing his item as a “0.40 sticker,” for $450. He also posted “PM for info,” a shorthand way of asking interested parties to send a private message via the Facebook Marketplace platform for more information. When contacted by the Journal, the seller said he was actually selling a Glock .40-caliber pistol.

Another seller in Beech Grove, Tenn., advertised a “Great little sticker 22 inches” for $300, next to an image of the logo for Savage Arms Inc., a gun maker based in Westfield, Mass. Over a private message, he sent photos of a .22-caliber semiautomatic rifle. Two other posters, contacted by the Journal, confirmed they were selling firearms, not stickers.

Those are some pretty blatant examples of folks who aren’t trying too hard to disguise their intentions. You might have been able to get away with selling toilet paper for $450 earlier this year, but not a sticker. How many other would-be sellers are using the platform with more subtlety and finesse? It’s quite literally impossible to know, but I’m guessing that for every idiot advertising a sticker for hundreds of dollars, there’s at least one more user who’s more low-key in their sales pitch.

The private sale of firearms is legal in the U.S., and while sales across state lines are meant to be funneled through licensed gun dealers, prosecutions are rare when they aren’t. People barred from owning guns, due to state or federal restrictions, can turn to online exchanges and social-media sites to avoid background checks when making a transaction.

Like the rest of the site, Facebook’s Marketplace platform uses a combination of artificial-intelligence algorithms and human moderators to weed out posts that violate its policies, such as ads for guns, drugs or animals, the company says. Last year, in response to the Journal’s reporting on guns being marketed as boxes or cases, a group of 15 Democratic senators, including now-vice-presidential candidate Sen. Kamala Harris, wrote to Facebook demanding information on how it polices gun sales on Marketplace.

Facebook responded to the senators’ questions in a letter saying it was building new tools to better detect bad behavior, and increasing its team of people who reviewed listings on its Marketplace. Sen. Bob Menendez (D., N.J.), who spearheaded the government’s inquiry, said the continued gun sales suggested Facebook’s reviewers were doing a “lousy job.”

Anti-gun politicians rarely let practicality or common sense stand between them and their anti-gun agenda, but their objections that Facebook isn’t doing enough to crack down on the sales fails to acknowledge one simple fact: the illicit market will always find a way. People are also using Facebook to sell illicit drugs, for example, often employing the same strategy of using code words to try to get around both Facebook policy and federal law, though in some cases sellers were brazen enough to employ hashtags like #buydrugsonline (which I suppose is the drug dealer’s version of being dumb enough to advertise a sticker for $450).

Sure, Facebook could try to tweak their algorithm to automatically flag sticker sales that include a price of more than, say, $20, but the sellers would likely just stop including a price in their posting. What does Facebook do then? Stop all sales of stickers? The sellers would simply find a new code word. You’d probably start seeing ads for Glockenspiels or SIG-natures from famous people like John Moses Browning instead of offers for really expensive stickers, but the illicit market would remain.

I realize, of course, that this isn’t a position that Mark Zuckerberg and Facebook can take publicly. To be seen as good corporate stewards, they need to be seen as doing something to ensure compliance with their policies. As much as I’d love for Facebook to go full-Libertarian and drop all their rules on advertising, that’s simply not going to happen. There is something that the tech titan could do, however, that would be practical, even if it didn’t eliminate the illicit market completely.

The first thing Zuckerberg should do is rescind the current policy that bars firearm retailers from advertising. If people are using the platform to find guns, as is clearly the case, Facebook could nudge those would-be buyers towards retail establishments where background checks are performed while reducing the demand for private sales.

In conjunction with that policy shift, Zuckerberg announce that 100% of advertising revenue from firearm retailers will be devoted to improving the company’s policing of its policy barring private gun sales. Now, all the problems I outlined above will still exist, but if the company hires more humans to scan and screen ads, it could at least make it a little more difficult to conduct the private transfers.

The black market will always be there, no matter what policies Facebook or the federal government choose to put in place. The anti-gun bloviating from people like Sen. Menendez and Kamala Harris may make for good soundbites, but they ignore a fundamental understanding of how markets work (not to mention how many Americans want to own a gun). By banning ads for firearm retailers, the social media platform is inevitably, though unwittingly, pushing its users towards the private market. The answer isn’t to double down on an anti-gun mentality, but to recognize the legitimate reasons why many Facebook users want to exercise their Second Amendment rights and to actually help them to do so.