You should be concerned about unmarked police cars. It's not that hard for the general public to pick up a used police interceptor with the lightbar and markings removed at auction. Imagine driving down a country road, alone and late at night, and someone pulls up beside you in an unmarked car claiming to be a police officer. Can you be certain that person is a police officer? Maybe it's someone pretending to be a police officer in order to rob you. If you're a woman or a teen, it could be a sexual predator. You don't know. The only way you can be certain that the person pulling you over is a law enforcement officer is that they are wearing the uniform of the day for their department, driving a clearly marked police cruiser with a lightbar on top.