Plastic is a capacitor and holds a static charge. A simple ionizing gun neutralizes any latent charges in the plastic. If you want to see static charge prevention in action go to a paint or munitions factory where a stray static spark can make a real mess.
With vinyl, the static discharges across the stylus to the cantilever of the cartridge making a pretty noticeable "pop". Anti-static guns, mats, and brushes have been around forever. There are some silly things that some audiophiles do, this isn't one of them.