Shake Shack is trying out a four-day work week in some of its stores, CEO Randy Garutti told a Las Vegas audience yesterday. "That's a big thing. Nobody's really been able to figure that out in the restaurant business," he added. "If we can figure that out on scale, it could be a big opportunity."

Maybe. But a closer look might tell you this "big thing" really may not be so big after all. To begin with, it applies only to managers, not to the cooks, servers, and cash register personnel who make up the bulk of Shake Shack's work force. The growing popularity of four-day work weeks stems from experiences at companies who've found that when employees work four days instead of five they turn out to be more productive and more creative at finding solutions to problems, as well as happier with their own work-life balance. The catch is that these experiments have taken place in offices, with white-collar employees who earn annual (not hourly) salaries. Their work consists of things like crunching numbers and writing reports, with a lot of flexibility as to when and how they do it.

If your job is making shakes and burgers when customers order them, then you don't have that kind of flexibility. You're paid for the specific hours you work, and since "not enough hours" is one of the most common complaints about Shake Shack on the employer review site Indeed, reducing hours for hourly workers won't make them happy. Most Shake Shack managers aren't paid by the hour, although a company representative explained by email that they typically work a 40 hour week, and where this program is being tested (Los Angeles, Dallas, San Antonion, and Detroit in addition to Las Vegas), they spread those 40 hours over four days instead of five.

Besides, entry-level restaurant team members may not be that difficult to find. Recruiting general managers, with three to five years' restaurant experience is much more of a challenge for Shake Shack. Garutti said in a February analyst call that the chain will open 36 to 40 new stores this year. But it could open 100 new stores if it could hire all the general managers it wanted. In fact, on the same call, he announced a new equity program for general managers giving each an additional $10,000 of stake in the company in an attempt to reduce turnover. Both moves seem designed to grab potential recruits' attention.

Shake Shack wouldn't be the first U.S. restaurant chain to try this approach. Aloha Hospitality, which operates two restaurants in Alabama, instituted a four-day work week for its managers last fall, allowing them to have two-day weekends, all too rare in the restaurant industry, along with an extra day off each week. That company also cited the difficulty of hiring qualified managers as the biggest reason for the change. 

But if managers get the benefit, the whole restaurant has to work to make this program viable, according to Aloha CEO Bob Baumhower. "You've heard the phrase 'it takes a village,' well in our case it takes a team!" he said in a statement about the four-day work week. "Everyone has to buy in, go the extra mile and support each other to make it work."

That approach seems to be working for Aloha, a much smaller operation. But how will it work for Shake Shack, where rank-and-file employees already wish for more hours and report to Indeed that they're expected to work very fast and get a lot of done in the hours they do have? Will they want to "go the extra mile" before heading off to a needed second job because their average pay is around $12 an hour? Especially when the managers they're helping out earn $50,000 a year and up--not counting the $10,000 equity bonus Garutti just announced?

Maybe they will. It could be they'll happily pitch in and cover for their better-paid bosses during those extra days off. But probably not. As Garutti noted, no other big player in the restaurant industry has figured out how to make a four-day work week viable. Maybe there's a good reason.