In the Zombieland franchise, whenever it's Tallahassee who picks out the gang's ride, he spray-paints the number 3 on its front doors. This dates all the way back to the Caddy SUV he was driving when Columbus first met him. Has the purpose of this been canonically explained?
The writer(s) were/are fans of Dale Earnhardt:
Earnhardt drove the No. 3 car for the majority of his career,
Fans began honoring Earnhardt by holding three fingers aloft on the third lap of every race,
So, it's an honor to the late legendary race car driver.