Still, the fast-food giant expects franchisees to follow state, local and federal laws.
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Chicken chain Zaxby's said it looks to local law and to its licensees to make the decision about what's best for their individual markets.
But following the Chipotle decision, Zaxby's is a taking a second look at its policy.
"Obviously, this is an issue that is becoming increasingly contentious, and as we continue to grow our number of restaurant locations and geographical footprint, it's something that we must examine further in order to determine how best to move forward," a representative said.
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While neither Chipotle nor Starbucks has banned firearms outright, it's within their legal right as a business, Spitzer said.
"I cannot think of a state offhand that does not give a private establishment some ability to control gun carrying within it," Spitzer said. "Generally speaking private businesses have a recognized ability to say that customers or employees cannot carry guns in if they make that policy known."
As gun right activists tote firearms openly to establishments to make a statement, Spitzer said he's seen more private businesses ask customers to leave guns at the door.
"That's been met in part with more resistance because average people tend to recoil when they see someone walking around with a gun," he said.
"Companies are not interested in controversy," Spitzer added.
A variety of chains including TGI Fridays, Subway and Cheesecake Factory declined to comment to CNBC about their gun policies.
—By CNBC's Katie Little