"Well, it's on," Ballance replied.
"It is a third-degree felony," the cop said. "If you want to push it, you can go to jail for it."
"Well, I'm pushing it now," Ballance said.
Ballance snapped pictures of the officers. One of the cops delivered a blindside tackle. Ballance had to be treated for injuries and cardiac symptoms at a hospital on the way to the county jail. At the hospital, officers refused to let Ballance use his recorders to communicate with doctors, court papers said.
In Portsmouth, N.H., earlier this month, Adam Whitman, 20, and his brother were charged with wiretapping, a felony in the state for videotaping police on the Fourth of July when they were called to a party and ended up arresting 20 people, many for underage drinking.
A police spokesman told ABCNews.com that the wiretapping charges were being dropped.
Across the country, arrests such as these highlight the growing role of witness video in law enforcement. A dozen states require all parties to consent before a recording is made if there is a "reasonable expectation of privacy." Virginia and New York require one-party consent. Only in Massachusetts and Illinois is it illegal for people to make an audio recording of people without their consent.
"The argument is, 'Well, can a police officer beside the highway have a private conversation with somebody that they pull over?'" said Joseph Cassilly, the Harford County prosecutor handling Graber's case.
Cassilly added, "Suppose a police officer pulled you over and he wanted to have a talk with you. 'Sir, I smell alcohol on your breath. Can you talk to me about how much you've had to drink? Would you want somebody else to stop by and record that and put it on the Internet?"
Rocah of the ACLU disagreed.
"It's not that recording any conversation is illegal without consent. It's that recording a private conversation is illegal without consent," he said. "So then the question is, 'Are the words of a police officer spoken on duty, in uniform, in public a 'private conversation.' And every court that has ever considered that question has said that they are not."
Rocah said actual wiretapping prosecutions, though rare, are happening more frequently. But intimidation with the threat of arrest for taping the police is much more common.
"Prosecution is only the most extreme end of a continuum of police and official intimidation and there's a lot of intimidation that goes on and has been going on short of prosecution," he said. "It's far more frequent for an officer to just say, 'You can't record or give me your camera or give me your cell phone and if you don't I'm going to arrest you. Very few people want to test the veracity of that threat and so comply. It's much more difficult to document, much more prevalent and equally improper."
In many jurisdictions, the police themselves record encounters with the public with dashboard cameras in their cars.
"Police and governmental recording of citizens is becoming more pervasive and to say that government can record you but you can't record, it speaks volumes about the mentality of people in government," Rocah said. "It's supposed to be the other way around: They work for us; we don't work for them."