As after most mass shootings in this country, the murder spree conducted by Jason Dalton in Kalamazoo, Mich. isn’t going to turn our attention to the gun lobby. Instead, this time, we have a villain that is far flashier and still maybe vulnerable: Uber.

Dalton was an Uber driver who reportedly picked up passengers in between pulling into parking lots and killing unassuming strangers. This is a very inconvenient fact for Uber, which is fighting local and state governments all over the country, and now has to contend with the notion that any of their drivers could turn murderous at a moment’s notice.

As Fusion reported today, Uber does have a gun policy. It is very brief and is titled “Uber Firearms Prohibition Policy”:

We seek to ensure that everyone using the Uber digital platform—both driver-partners and riders—feels safe and comfortable using the service. During a ride arranged through the Uber platform, Uber and its affiliates therefore prohibit possessing firearms of any kind in a vehicle. Any rider or driver found to have violated this prohibition may lose access to the Uber platform.

Uber bans its drivers from carrying weapons while on the clock, and threatens to fire drivers who do not comply. There is only one (big) problem with this policy: it’s entirely unenforceable.

This is a function of Uber’s very being. A driver gets into his or her car and opens the Uber app and starts picking people up. There is no way to prevent that driver from bringing a rocket launcher into that car, let alone a concealed handgun.

Uber’s very business model also means that there isn’t even a functional, incentivized self-enforcement of the policy. Fusion notes that New York City’s Taxi and Limousine Commission installs dividers that separate drivers and passengers, and that a yellow cab driver carrying a gun would risk losing his or her taxi medallion, which costs hundreds of thousands of dollars and is necessary for operating a cab in the city.

But Uber doing something like installing barriers in cars would completely upend their business model, and the stakes for drivers—who mostly work part-time to pick up extra income—are low enough that they might carry a weapon even if it means they could be banned from working for Uber. Fusion cites a quote given by an Austin, Tex. Uber driver to a site called The Trace about riding with a gun:

One Reddit user who claims to drive for Uber tells The Trace he carries a concealed weapon on the job in full knowledge of Uber’s policy. “I carry because I would much rather lose the ability to work with Uber than be robbed, physically assaulted, or need to defend myself and be unable to,” he wrote in a message.

Of course, this doesn’t exactly apply to Jason Dalton, who just decided to go on a shooting rampage. But it does highlight that along with overtaking the entire public transportation industry, Uber also has to figure out how to make sure its drivers won’t—and can’t—shoot people.