I just learned about this but it seems that during the last Argentina world cup match many stores were robbed a few blocks away from where I live. During the matches, the streets are deserted, even the cops stay indoors glued to the TV so its ideal for criminals.
The local store owners got together and agreed to close down when the national team is playing next time. Its also a good idea for the average folk as well.
Also worth mentioning, that those driving during the game or just before it starts usually drive like freaks trying to get wherever it is they are going fast, so its better to stay out of the streets as well.