It's not an urban legend or superstition. It's a function of the lizard brain. It adds an extra "interesting" attribute (many things can do this, color is not the only one) that makes you more likely to get stopped. It's the same reason fishing lures are painted brighter than the natural colors of the things they are trying to emulate. It makes the brain go "hey what's that?". In both cases the object cannot trigger the "prey" workflow if the brain doesn't notice it.