The Blind Man: There is nothing a man cannot do once he accepts the fact that there is no god.
The Blind Man: God? There is no god. It's a joke.
Money: Just because he's blind doesn't mean he's a saint, bro.
The Blind Man: She was pregnant with my child. Now you've killed them both.
Alex: It's kind of messed up to rob a blind guy, isn't it?
Chosen answer: As we see in the film, the houses they burgle have all purchased security systems from Alex's father. This makes it easy for them to gain access to the houses without triggering the alarm. However, if they committed a string of burglaries in which no alarms were triggered, people would eventually put together that customers of the same home security company were being burglarized and would point to them all being inside jobs. By tripping the alarm once they finish, they make it look like a standard break-in.
Phaneron ★