If something is stolen from you, report it to the police. No big investigation is going to occur, but you will get a police report to give to your insurance company.
In recent years, Brazil has gotten quite strict about drink driving. Police checkpoints stop cars at random.
The penalties for drug possession are harsh, and you don't want to end up in a Brazilian prison. Some police checkpoints are set up outside nightclubs to stop taxis and give the full pat down to club-goers on their way home (hint, don’t carry anything!). Police along the coastal drive from Rio to Búzios and Rio to São Paulo are notorious for hassling young people and foreigners. Border areas are also a danger, particularly around the Bolivian border.
If you are arrested, know that you have the right to remain silent, and that you are innocent until proven guilty. You also have a right to be visited by your lawyer or a family member.
A large amount of cocaine is smuggled out of Bolivia and Peru through Brazil. Be very careful with drugs. If you’re going to buy, don’t buy from strangers and don’t carry anything around with you.
Marijuana is plentiful in Brazil and very illegal. Nevertheless, it’s widely used, and, like many other things in Brazil, everyone except the military and the police has a rather tolerant attitude towards it. Bahia seems to have the most open climate.
If you’re coming from one of the Andean countries and have been chewing coca leaves, be especially careful to clean out your pack before arriving in Brazil. Sentences are stiff even for possession of coca leaves.
Because of the harsh penalties involved with possession or apparent possession, it's wise to stay away from drugs in any form.