Last winter I was "pulled over" walking in Palermo Soho/Plaza Italia. (~Paraguay approaching Thames maybe) I was texting and looking down. It was ~3am, I was cutting along Paraguay rather than heading to or from Santa Fe and it was cold. Because it was cold I had my collar UP and a "beanie" (wool cap) on my head. Apparently this is too suspicious to ignore.
I was stopped by a policeman who crossed the street to approach me and he was slowly followed by his partner. Like I always do when dealing with police here, I immediately broke into English and only later stammered through a bit of Spanish. (Same thing as when I'm trying to jump to the front of a line at a Boliche... because it usually works.)
This guy was all "tranquilo", but he wanted to see my "documentos". I showed him my drivers license from the States. Then he wanted me to empty my pockets. THIS is when I thought "This fucking guy is going to rob me." I had some cash and I had a small digital camera on me that night. I was sure he was going to try to take something.
But after talking for a while, taking everything out of my pockets and explaining that I was walking to Borges to walk down to Santa Fe because it was a well lit street, he let me go.
This wasn't the first time I've been questioned by the cops in my life. In LA I was pulled over because "I was the only white person around here." (Apparently you're not supposed to be white and drop off a friend who lives near the Great Western Forum in Inglewood.)
PS- A cop tried to stop me as I was walking across that field from the buses to the Bombonera on opening day back in September. My friend was with his son and half-brother (that could practically be his son) and I was walking off to the side trying to take a picture of the three of them. They're porteños and I'm obviously not.
The cop tried to stop me, but then my friend stepped in and told the cop NO, he's not going to show you his papers, we're going to the game, and we kept on walking. My friend doesn't speak any English, so sometimes things are lost in translation, but I think that he was saying the cop was going to probably want some money to let us keep walking.