The United States Supreme Court reversed. According to the Court:
We resolve this question by asking whether a reasonable person in Brendlin’s position when the car stopped would have believed himself free to “terminate the encounter” between the police and himself. Bostick, supra,at 436. We think that in these circumstances any reasonable passenger would have understood the police officers to be exercising control to the point that no one in the car was free to depart without police permission.
Agreed. When the police stop a car, no one believes he is at liberty to simply exit the vehicle and walk away. SCOTUS got this one right.