Short answer: No. This is a myth.
There are people that come from all walks of life in Okinawa. People originating from other areas might be led to believe that this is true. For instance, if one is from Ohio, they might be more inclined to believe this as they issue “scarlet plates” or plates with red lettering on a yellow background, for DUI offenders there.
However, in Okinawa, they are nothing more than vanity plates known in Japanese as jiko-shiki.