The “Trooper Two Step” or “Kansas Two Step,” takes advantage of the, often murky, distinction between whether somebody is legally being ”detained” or in a “voluntary encounter” with law enforcement.
Let’s start with the rule: during a traffic stop, you can only be stopped (detained) for as long as it takes the officer to write the ticket.
This assumes they don't develop probable cause during the stop.
Probable Cause could develop, for example: if you’re pulled over and smell like booze. Now, they have probable cause to investigate a new crime (DUI) and to continue the traffic stop (detention).
But, if no probable cause develops, they have to write a ticket and let you go about your business.
That’s Where the Trooper Two-step (Kansas Two Step) Comes Into Play.
The trooper two-step (Kansas Two Step) happens after a traffic stop:
First, the officer gives you your license and insurance back and says “you're free to leave.”
Then, the officer takes two steps to the rear of the car.
Then, the officer turns around and comes back to your window and says:
"Hey, by the way. You know we've got a lot of problems here with guns, drugs. You don't have any rocket launchers or drugs in the car, do you? You don't mind if we search?"
(Trooper two-step is also known as "the Kansas Two Step")
Let’s pause right here in the traffic stop procedure. Since, the officers gave back your license and told you that “you're free to leave”, a line has been crossed. This is no longer a traffic stop, because they told you “you're free to leave.”
Now, this is a voluntary encounter.
Before they gave you your license back, they needed to have some kind of reasonable suspicion – or evidence to believe you've committed a crime to ask you to search your car. Now, since this is a “voluntary encounter,” they don't need any reasonable suspicion, now they don't need probable cause.
What do you do if you're in a situation like that, and you feel like they've done the trooper two-step to you? Just ask: "Am I free to leave?"