VALLEY CITY, N.D. – A cup of coffee can fluctuate in price, but customers can always expect to pay within the ball park of a few dollars. According to a report from Springwise, that low price point means that cafés are ripe for experimentation with payment systems. For instance, a café in France that charges customers more if they’re rude. Now, there’s The Vault, an unstaffed cafe that gets customers to make their own coffee and show some honesty when paying.

Located in a former bank in Valley City, North Dakota, the venue doesn’t have any baristas. Instead, the café serves coffee from a Keurig K-Cup machine and a professional brewing machine, alongside other soft drinks and individually-packaged snacks. Customers simply take what they want and check the price board to add up their final bill.

They can then place cash or a check into a slot in the “honesty box,” or use the self-service card reader. Exact change isn’t needed — it’s up to customers to decide if they want to round their bill up or down … or pay at all, for that matter. Although the venue keeps security cameras, there’s no other incentive to be honest, but the café has found that its customers have paid an average of 15 percent more than the listed prices.

While the “honesty policy” isn’t likely to become standard for retailers anytime soon, chains like Panera are using a similar model for social good. The St. Louis-based chain first opened a pay-what-you-like location in its hometown in 2010 and has since opened four other locations across the country.  Dubbed Panera Cares, these special community cafes meant to aid those who cannot easily afford or access healthy food are the brainchild of Panera Bread CEO Ron Shaich, and offer a case study in how a for-profit company is navigating philanthropy and bottom lines.

Although customers and industry watchers initially wondered how a menu with no fixed pricing would work, the cafes are part of a larger plan for the chain, which last month launched a comprehensive food policy.  At a conference earlier this year, Shaich admitted that some — but not most — customers have abused the pay-what-you-want cafes. But the company remains dedicated to fighting domestic hunger and food insecurity.