legal fog lamps?
Re Malc's question.
I am far from an expert, but the easy answer from the U.S. perspective concerns how one might use/misuse the fog lamp. This also includes the lamp's mounting position (above/below bumper) and, I suspect even the lamp's beam and intensity.
While there are some basic Federal rules set by the Federal Department of Transportation, each State has its own laws and its own interpretation/enforcement of its own laws. There was a time when using anything other than an approved sealed beam head lamp was cause for a citation and correction. Now, with the advent of so many multipurpose vehicles including 4WD "off-roading" Cadillacs with 2' rims and light bars to rival anything used by Boeing and Airbus, the issue is not as much what is legal/acceptable, but rather what is enforced.
Dark window tint, loud noise, lack of brake/tail lights are more likely candidates for citations. Common sense suggests that a very bright rear fog lamp left on while driving might be interpreted by Texas Ranger Chuck Norris far differently than Ranger Clodagh Rodgers. One might view the light as a a safety device, while others might deem it a hinderance or potential deterrent to public safety.
(I doubt there would be much disagreement if the red lamp was placed in the front of the vehicle, even if you can prove terminal dyslexia! Unless, you suffer from that malady and you are one of the Kray bros! lol)