The group advocates putting your license, registration and insurance information in a plastic freezer bag and holding them against your car window along with this flyer:
I remain silent. No searches. I want my lawyer.
From their website:
The idea is that you do not roll down your window but rather press the flyer up against the window so police can read it. You show them your license and other papers through the window.
The purpose of the bag is to keep the driver from having to roll down their window and potentially putting themselves in danger of police “lying” and saying a driver’s speech is “slurred” or that they could smell alcohol or drugs coming from the vehicle.