Shake Shack Founder Requiring Proof of Vaccination for Customers at Company's Other Restaurants: 'You Can Dine Somewhere Else' Danny Meyer, the CEO of Union Square Hospitality Group, announced that all restaurants overseen by the company (excluding Shake Shack chains) will require both employees and dine-in customers to show proof of vaccination.

If you're craving one of those cult-favorite Shack Burgers from Shake Shack, you might eventually need to show proof of vaccination.

However, if you're craving any food from any of the other restaurants overseen by the chain's founder's company, you're going to need to show proof soon.

On Thursday's episode of CNBC's Squawk Box, Shake Shack founder and CEO of Union Square Hospitality Group, Danny Meyer, announced that restaurants overseen by the company will require both employees and dine-in customers to show proof of vaccination in order to enter.

This does not include Shake Shack as a chain itself.

"I'm not a scientist, but I know how to read data, and what I see is that this is a crisis of people who have not been vaccinated, and I feel strong responsibility, on our part as business leaders, to take care of our team and our guests, and that's what we're doing," Meyer said.

Union Square Hospitality Group is the parent company of beloved New York City hotspots like Gramercy Tavern and Union Square Cafe.

Related: Shake Shack Received, Then Returned, $10 Million in Stimulus Funding

As for Shake Shack, Meyer said that the fast-casual chain will "make the appropriate decision for them at the appropriate time."

"You cannot eat or drink with a mask on," Meyer continued. "The one thing you can do is be vaccinated."

However, many on Twitter seemed to be confused, thinking that Shake Shack itself was mandating the new policy across all restaurant locations and thus, sparked a massive debate. Shake Shack itself has not taken a stance or made a statement yet regarding Meyer's comments or any upcoming policy.

"If you really want to go unvaccinated, you can dine somewhere else, and you can also go work somewhere else," Meyer asserted.

A pop-up on the company's website explains the new policy to future guests and customers.

"Please bring along either your physical Covid-19 vaccine card, your New York State Excelsior Pass, your relevant state-provided vaccine pass, or a photo of your vaccination card to share upon arrival," the company says. "Thank you for your understanding as we work to provide the most comfortable and safe experience for both our guests and our teams. We look forward to seeing you soon!"

The policy is set to go into effect on September 7.