When it comes to matters dealing with the police in Brasil, there are a few differences from their American counterparts. Let me say, up front, that all of the officers with whom I've come in contact in Santa Catarina with are really nice guys. They appear to be caring professionals who try to maintain peace within the communities they serve with kindness and understanding, albeit also with a firm hand.
With that said, I would suggest that you always treat an officer of the law in Brasil with the utmost respect. They demand it. Their very presence commands it. There are usually three levels of police protection in most cities--city police, state police, and military police (policia militar). Do Not Mess With Policia Militar! They are hard core devotees to the letter of the law in Brasil.
I remember my first trip to Brasil--we were staying at a hotel in Jaragua do Sul--and we went out after breakfast to go see family. There were policia militar stationed at the front of the hotel, swat vehicle in plain view and M-16 rifles drawn. My husband told me not to look at the officers and so I kept my head down. We got in our car and drove off. My husband explained that there was probably a tip that drug runners were on their way in or out of town and the military police were looking for them. You see police officers with guns drawn everywhere in Brasil. They are always ready for action. It's a little unnerving at first, but you eventually get used to this regular sight.
While traveling by car, truck or motorcycle in Brasil, you better be sure to have your license, registration, title and insurance information handy at all times. There is no such thing as "Oh, officer, I forgot it at home." Believe me, they will confiscate your car on the spot, no questions asked. Police in Brasil regularly conduct what is commonly referred to as "blitzes" and they are just as you think the word implies. They will set up alongside the road and flag down cars at random, and if you don't have your paperwork, you are in for a rude awakening. Many blitzes target motorcycle drivers as there is not only alot of corruption in buying and selling stolen motorcycles (same for autos), but many drug dealers hire motos to deliver the goods. Sometimes you'll see blitzes set up alongside the road and right before they get there, motorcycle drivers will turn around and take another route. Once caught, motorcycles are confiscated and if the drivers are caught with illegal substances, they are arrested. You'll see sometimes ten or more motorcycles by the side of the road waiting to be taking to the impounding lot located next to the policia militar station.
Til then, tchau!