Among those practices is something cops call the "Kansas Two-Step." After pulling you over for a traffic violation and dispensing either a warning or a ticket, a cop starts walking away, but then turns back and asks, "Hey, can I ask you something?"

What feels like a friendly conversational question is actually intended to trick you. As Reason's Jacob Sullum explains: 

"Police are not supposed to continue detaining you after the ostensible purpose of the stop has been accomplished unless they reasonably suspect you are involved in criminal activity.

The two-step is designed to extend the encounter by making it notionally voluntary, giving the officer a chance to elicit incriminating information, ask for permission to search your car, and/or walk a drug-sniffing dog around the vehicle."