There are people whose very presence can make you feel threatened.
Sometimes it's because you just don't like the look of them. Other times, it's because they're wearing a uniform and striding toward you purposefully.
It seems, though, that some police officers are feeling automatically threatened by those who choose to film them on their cell phones.
In what is certainly not the first incident of its kind, police in Cutler Bay, Fla., arrested a DJ who was spinning some records at a local store.
As CBS 4 reports, Lazaro Estrada was spinning away when the police rolled up to arrest the store owner, Andre Trigiano, on outstanding traffic charges.
Estrada thought the way the police acted toward the store owner was slightly outstanding too. So he began to film events on his iPhone.
On the footage obtained by CBS 4, Estrada seems to be far away from the proceedings. He is filming from inside the store. He had been told to back away.
"I backed off into the building and I stayed behind the glass doors. Obviously, all I had was my phone in my hands in clear sight. And he only told me once. I did what he told me," Estrada told CBS 4.
He added: "The video speaks for itself."
He was, however, arrested for obstruction of justice. In the arrest report, Officer Michael Valdez said of Estrada: "I was threatened by his presence."
Goodness, I can think of several people whose presence undermines my comfort. I've never thought of having any of them arrested. Perhaps I might try it.
"Police are afraid of the citizenry with cameras," said Estrada's lawyer, Jonathan Perazzo.
There seems to be some evidence of this from all over America. There was the case last year, when police in San Diego seemed to call a Samsung Galaxy a "weapon."
In Bakersfield, Calif., also last year, police were accused of taking a cell phone and erasing the evidence it contained of their behavior.
On Long Island, N.Y., a police officer stepped into a private driveway in an apparent attempt to stop someone washing his car on his own property. This, happily, was filmed a cell phone for all to see.
In the case of Estrada, he can be heard telling the police officer: "I can record all I want."
The arrest report accuses him of not complying with police orders to back away. So he wasn't just charged with obstruction of justice, but with resisting arrest without violence.
However, the video shows that the officer performing the arrest isn't sure at first what he's going to arrest him for.
The Miami-Dade police department told CBS 4: "The arrest report speaks for itself, and Mr. Estrada is entitled to his day in court."
So now we have a video and an arrest report that both speak for themselves, but don't seem to be speaking entirely the same language.
Cell phones have become a combustible force in the sometimes tense relationship between police and the citizenry.
The Supreme Court is considering today whether to allow police to seize and search cell phones without a warrant.
Some might imagine that there's a certain imbalance between a police officer searching through your cell phone without a warrant and one arresting you for filming him on it while he's performing his duties.