I’m not sure you wouldn’t get stopped in some states with that bumper sticker. Lights on cars are safety and signaling devices. Having extraneous lights on a car is a safety issue to not just the driver of the car but to drivers and occupants of other cars and pedestrians.
Furthermore, I just read that Texas prohibits all lights that are not federal DOT or SAE approved. I can guarantee that no Christmas lights manufacturers pay for DOT SAE certification.
In Texas, they would be considered a hazard because of possible distraction of other drivers (rubbernecking and possible cause of a preventable accident).