In multiple recent incidents across the country, police officers have been denied service in some form — food, access to restrooms — by employees. Local news and social media quickly helped publicize the interactions, and often the franchise owner, if not the larger company, ended up apologizing (and giving police officers free meals), reports the New York Times .

Some say that these incidents alone signal a shifting attitude toward law enforcement officials among service industry workers. Samuel Walker, a criminologist and professor at the University of Nebraska Omaha known for his focus on police civil rights abuses, said that the change was a reaction to publicized police misconduct.

"I think it's wrong," Mr. Walker said. "If you've got some criticism of police, this is not the way to do it."

But Dennis Slocumb, the vice president emeritus of the International Union of Police Associations, was unsure whether the incidents constituted a trend.

A Gallup survey conducted in June showed that confidence in the police nationally is "the lowest that it's been in 22 years," though it pointed out that, overall, 52 percent of people expressed "a great deal" or "quite a lot" of confidence in the police.

Slocumb said that, even if an action was expressly political, it was not worth making a fuss over.

"If somebody wrote black lives matter on my cup, I wouldn't get all exercised," he said. "I would prefer that somebody refuse to serve me than do something to my food."