Upvote:1
I've spent few years in South America. Thieves that you are describing will try to take anything they can get - your bag, cell phone, camera, wallet, sunglasses, hat ... they might even ask you to take off your shoes. They are not targeting documents in particular.
My passport was all the time at home, while I walked around with a copy of the passport's photo page.
Upvote:7
The state of SΓ£o Paulo has this annual report called Perfil do Roubo that shows what were the objects taken in thieves. I live in Brazil and I can affirm this report represents other Brazilian cities as well.
According to the 2021 report, 40% of the occurrences included the victim's documents. Only 10% of the occurrences exclusively targeted the victim's documents.
They're not interested in your passport. You don't need to worry about that 40%. Brazilians carry their national ID card in their wallets, and that's why the numbers for stolen documents are high.
So keep your passport somewhere safe. Not in a bag someone can take from you. I usually have one of those "hidden" money belts I keep my documents in.