May be. Speaking for my city:
You shouldnt walk on the streets showing money of cellphones or whatever of much value. Specific places are worst, principally close to favelas (ghettos). It is a general rule, for tourists and even native people.
Restaurant, shoppings, and any other place is fine!
But I think Lakes region seens to be one village, a small city. Here in my state, villages and small cities are very secure. Its like violence still didnt come there.
I want to scare nobody, but unfortunately its the true of my country.
Tomka! Nice choice and good luck on your trip !! You still have lots of other places to visit.. After if you like beaches, search '' Praias do Ceará'', you will be amazed for sure.