IN THE STATE OF WASHINGTON, BLUE DOTS CAN BE LEGAL!

HA!

I KNEW IT!! 

"All lighting devices and reflectors mounted on the rear of any vehicle shall display or reflect a red color, except the stop lamp or other signal device, which may be red, amber, or yellow, and except that on any vehicle forty or more years old, or on any motorcycle regardless of age, the taillight may also contain a blue or purple insert of not more than one inch in diameter, and except that the light illuminating the license plate shall be white and the light emitted by a back-up lamp shall be white or amber."

(section 46.37.100 of the Revised Code of Washington)
I'd put some on the motorhome, but hoping to ship it to New Zealand when (if?) this place sells, and no sense pissing off the coppers there unnecessarily, eh?