My driver Tom and I are going down Randall Street today. Some guys are walking down the street. “They’re criminals,” Tom says, “roll up your window.” I do as instructed. Tom used to teach ex-combatants as part of their reintegration into society, so he knows a bunch of them.

Tom was staring intently at some guys outside, and a black SUV in front of us. Traffic was going slowly. “Watch this,” Tom says. “What?” I asked. “Just watch,” he said, hushing me.

Tom proceeded to narrate.

“Ok, look at those three guys, one, two three. See the driver of the SUV? They are going to take his phone.”

Literally one minute later, one of the guys banged the back of the SUV with his fist. The driver turned around to look at what was going on. Another guy grabbed the driver’s cell phone, which was on the dashboard. All three guys sprinted off. Four seconds later the driver realized what happened. He slammed on the brakes. (Tom, always ready for this kind of stuff, was a good 10 feet back.) The driver stopped the car (stopping traffic on the already narrow road) and started chasing the thief.

A group of guys watched laughing. They clearly knew what was going on. Tom shook his head at them.

“Now you know how it happens,” Tom said, “This is why I always tell you to put your window up.”