"It's going to get dicey real fast," said James Hodge, a law professor at Arizona State University. "This is far too big for everybody to cooperate for extended periods."
Already, prison authorities around the U.S. are releasing people to lessen crowding in jails and prisons where the virus could spread quickly among a crowded population, according to the Prison Policy Initiative that works to reduce mass incarceration.
City sanitation departments in the U.S. have police units, said Howard Markel, director of the Center for the History of Medicine at the University of Michigan. While they can make arrests, Markel said in an interview, "I don't know if they will."
"They carry badges and have all the rights and powers to take you away," Markel said. For instance, he said, sanitation police arrested "not a small number" of people in San Francisco during the 1918 Spanish flu outbreak for not wearing masks.
The federal CDC said it routinely monitors people arriving at borders and ports of entry for signs of communicable diseases, and can detain passengers and crew needed.
Authorities have "tremendous authority" to trace and isolate virus carriers, based on a "vast body of law" over communicable diseases, some of it dating back to tuberculosis and measles outbreaks in the early part of the 20th century, according to Henry Greenberg, president of the New York State Bar Association and a former general counsel of the state's health department.
Courts have recognized that governments need to protect the public from health threats. But officials must avoid excesses when they balance those concerns against individual rights, Greenberg said.
Disputes stemming from measles and Ebola outbreaks in recent years offer a glimpse of the legal backlash authorities could face.
A New York state judge in April tossed out an order by state officials banning unvaccinated children from all public places for 30 days in Rockland County following a measles outbreak. But the judge left intact an order prohibiting the children from entering schools or day care facilities.
In 2014, Kaci Hickox, a nurse, fought demands from two governors that she be quarantined after treating Ebola patients in Africa, before winning her freedom from a judge.