Its supposed to be a way for Jeep owners to 'atta boy' other Jeep owners for having a nice Jeep. Youre supposed to buy a bunch and keep them with you, if you see another Jeep you like youre supposed to leave a duck on their hood to let them know they did a good job buying a Jeep. Then the owner of said Jeep comes back and finds the duck from a stranger, feels good about themselves and puts the duck on their dashbaord as a trophy. The more ducks on your dash, the more alpha you are in the Jeep community.

I came to the comments seeking the same answer