The chances of a tourist being robbed in Brazil are pretty good. Prior to the World Cup which was held in 12 Brazilian cities in 2014, the United States Department of State described armed robbery in Brazil as “a major concern”. I would not just be worried about robbery, but I would also be worried about contracting yellow fever.
The same US State Department issued a travel warning in January, 2017, about an outbreak of yellow fever, advising tourists to get a vaccination before travelling to Brazil. Also in July of 2017, this same agency warned of increases in crime on and around the Corcovado Mountain hiking trails.