Police are just like everyone else, but with no one looking over their shoulders.
But, if you have drugs in your car, aren't you guilty anyway? Lies are one thing, I know. It'd suck to get pulled over for some lame traffic violation, have drug dogs called while you wait, have the dogs search your car, find nothing, and then you go on your merry way - but that'd be the last time the cops fucked with you, or you could then sue their pants off for harassment. This attack method is double-edged, for both sides.
It almost makes me want to become suspicious, just so I can get a nice, thick and juicy lawsuit going on, as currently I hate the local cops about as much as I hate the local drug dealers.
The problem is that if even if you don't have drugs in your car they will bring a dog. The dog may not even be trained to sniff drugs. The dog will (of course) indicate there may be drugs in the car and then they will continue ask you for your permission to search the vehicle. If you deny permission to search they will impound your car, which is a major inconvenience of time, money etc. Cops then have lots of options when the car is impounded...ranging from just making you pay the impound fee, to planting drugs in the car. Regardless if no drugs are found, you will be out a car, out some money to get your car back, possibly framed and of course have your 4th amendment rights stripped away. "Oh, sorry the dog found a false positive" or some other BS. Good luck winning a lawsuit for an unreasonable search when they don't find anything. Welcome to America.