AFAIK the yellow signs are "advice" rather than law. I make a point of at least doubling the "advice", visibility and governing speed limit permitting.
Why would you make a point of doubling the advised limit? I can't imagine your stopping ability is actually twice as good as average.
In other words, for no reason other than hubris/machismo, you're choosing to significantly increase your likelihood of wrecking your car (and/or others' vehicles) and possibly killing or maiming yourself (and/or others).
It just takes a bit of black ice, loose gravel, spilled oil, confusing shadows, distractions in the car (like spilled coffee) or outside of the car (like a bird or rock hitting your windshield, or a deer leaping into the side of your car -- to use examples that have happened to me personally), another distracted driver who has veered into your lane, and boom, you're done. They're done. Maybe the 12-year-old riding a bike on the side is done.
Sorry, this is an overreaction to a throwaway comment, but bad drivers who think they're good drivers are friggin' everywhere, and the resultant loss of life and limb is staggering.
