answer:I have a friend whose 26 yr old daughter is roaming around Brazil now, alone. Her mother is terrified, but the girl seems unfazed. She has troubles using a cell phone and finding computers when she is out of the cities. She didn’t communicate w. her parents for 10 days and they were pretty edgy, but she was fine. OTOH, the cities are where the gangs are and the danger to American tourists is highest. Make sure that she doesn’t travel alone, particularly at night. I would really grill the staff at the U of Del, who are responsible for the care and safety of the students. They will know; and there is a lot of info online about tourism and safety in Rio and Sao Paulo, for example. And I would try to have a regular time for a check-in from your daughter, barring contingencies.