It actually is a phrase that means the same as "Give A Hoot, Don't Pollute". It is on "Do not litter" signs in the state of Texas.
Man reading sign: Don't mess with Texas.
Other guy: What the fuck does that mean?
Man: I'm not sure, but I don't think we should be throwing these dead bodies here by the look of this sign. It says littering is a $500 fine.
Other guy: Shit.