http://www.scstatehouse.gov/code/t56c005.php
SECTION 56-5-590. Stop.
"Stop," when required, means complete cessation from movement.
SECTION 56-5-750. Failure to stop motor vehicle when signaled by law-enforcement vehicle.
(A) In the absence of mitigating circumstances, it is unlawful for a motor vehicle driver, while driving on a road, street, or highway of the State, to fail to stop when signaled by a law enforcement vehicle by means of a siren or flashing light.
You highlighted the wrong part. Blue light bandits have flashing lights too.
Here's the important part: "(A) In the absence of mitigating circumstances, it is unlawful for a motor vehicle driver, while driving on a road, street, or highway of the State, to fail to stop when signaled
by a law enforcement vehicle by means of a siren or flashing light."
I doubt there's a state in the union that hasn't issued warnings about blue light rapists, where police advice people to drive to a well lighted location before stopping.
I'm a pretty big guy and well armed, but I would never pull over for an unmarked vehicle.
I've never had one make the attempt, but the closest was a "low profile" Arkansas State Police car. These have no visible lights, and are only marked on the right front fender and passenger door. I was on the interstate when I noticed a car pacing me in the left lane; I glanced over and see two troopers in full uniform, including Smokey Bear hats, looking directly at me. As soon as I acknowledged them, they dropped behind me and hit the (hidden) blue flashers. Of course I pulled over, because they made it obvious that they weren't just some silver Crown Vic with lights behind the grill.