People in Buenos Aires City, as with any large city, are used to being extremely aware of their surroundings — knowing that theft is a real problem. This is especially true on public transportation, and in what it seems to be part of a Darwinian race against people’s constantly updating cautionary measures, thieves operating on the subway system developed a new way of stealing: the so-called trepaventanas (window climbers).

How does this work? Basically, the thieves climb through the window of the subway as it starts to leave the station and snatch whatever victims might be holding in their hands. They also count on a female collaborator to spot their victims, so they are completely sure who they are stealing from. The fact that you are stuck in the subway car means you can’t get out until the next station, and most of the time you haven’t actually seen the person who robbed you.

Although the City Police monitoring center, where officials constantly check live feeds from the cameras placed in places like the subway, will put in a call to police on the ground as soon as they spot an episode, the thieves have already planned accordingly. They bring another outfit to change to fool the cameras. They call this onion method because they have layers of clothes.

This new trend in theft brings the shortage of police officers in the subway platforms back into the limelight. According to the Buenos Aires Metropolitan Police, there have been around 115 incidents that took place in the subway platforms since March. And those are only the reported ones.

It might be time to rethinking whether that window seat is really worth it.