Originally Posted by
MSPeconomist
Be careful too in Brazil about security around whatever ATM or currency exchange you use. Avoid any place that has people hanging around, especially a bunch of young kids. Watch also for people following you after a money or foreign exchange transaction. It could be a mugging setup.
I think your advice is warranted for Rio. My cousin married a Paulista and even he stays quite cautious about Rio. However, SP is like another big city anywhere in the world. Keep your eyes and ears open and you'll be good.