The vast majority of tourists that travel to Brazil enter and leave with all their possessions intact, nothing but good memories and do not need to draw on their travel insurance. This is not to say that security issues do not need to be considered or that you shouldn't have travel insurance. A little common sense is usually all that is needed to ensure you have a great time.
Everyone is justifiably worried about being robbed at gun point but focussing on this means the main dangers in Brazil get overlooked. They are so common most people pay no attention to them at all. They are roads and alcohol.
The biggest risk to your life in Brazil is travelling in a private motor vehicle. The US state department wrote this little gem:
"Brazil's inter-city roads are widely recognized as among the most dangerous in the world. The Federal Highway Police reported 120,000 accidents in 1998, but this is believed to be a very conservative figure. As is the case elsewhere in the region, poor driving skills, bad roads and a high density of trucks combine to make travel considerably more hazardous than in the United States. There are no laws requiring truckers to take mandatory rest stops, and they often drive for excessive periods of time. All major inter-city routes are saturated with heavy truck traffic, and for the most part have only two lanes."
The only point they missed was the culture of drink driving but on the whole it sums up the situation fairly well. Seat belts are generally only worn by those in the front seats because in Brazil anyone sitting in the back seat is miraculously protected from injury in the event of a car accident. If you are in an accident don't expect ambulance response times to equal those in your home country.
As you travel through Brazil keep a look out on the side of the road as you enter and exit towns. Typically there will be a police station and nearby a collection of smashed up cars left to remind you of what can happen on the road you are about to travel upon.
Brazilian drivers are quite happy to cross double yellow lines on winding roads to overtake, trucks tailgate each other and motorbike riders zip in between cars. On Christmas Day 2006 I watched as a motorcycle rider attmepted to overtake a car on a winding road, lost control, crossed in front of an oncoming car which hit him a full speed and catapulted his body through the air before it crashed against our passenger door. His bike and the car (pictured below) were complete write offs. By some miracle he survived with only cuts and bruises and all we had to do was wash his blood of our car.
You only have to go to a hospital emergency department on a weekend to see the number of accidents caused either directly or indirectly by alcohol. Telling young travellers not to drink is hopeful at best but abusing alcohol is the quickest way known of increasing your chances of problems occurring. Lost cameras, lost money, lost passports, getting ripped off by nightclubs or getting ripped off by taxis are just a few problems you can thank alcohol for and you do not have to be in a foreign country for this to happen.
With the help of a few drinks some people manage to quickly transform themselves into complete wankers. Young men in particular begin to feel like the toughest guys in the pub and need to prove it to their mates. If this is you, before you think of starting or finishing an argument consider this. You're the foreigner, you probably don't speak the language and you're most likely outnumbered. Are these the odds you want? If you're still not convinced know that Brazilian guys love Ju Jitsu and it is one of the countries most popular sports. You might even get a demonstration.