Raimundo, I know where you are coming from, certainly some see foreigners as there for the taking and when taken the view is "well they were gringos". No doubt about that.
Difficult to generalise but some of that culture has attracted equally unethical scam artists from overseas. It's just that the ones from abroad are more spohisticated about it. In my experience when abroad, it is my own countrymen that are first to put their hand in the honeypot and we foolishly thought we could trust them. Long and the short of it is that you can buy a cheap property in Brazil because it aint easy..if it was, everyone would be doing it!