Ok... A lot of fun answers. It was kind of a "hmmm...." question, so don't take it too seriously. Still... If they don't have a brake, they're not actually legal.

I don't think a cop is ever going to hassle a cyclist on a fixie - unless he plows into someone. I also don't think any bike shops will get raided for selling non-compliant bicycles.
For the most part I figure it's just a law that does not get enforced much, if at all. And let's be honest... we get away with stuff because we are on bikes. I've been known to exceed the posted speed limit, maybe not come to a COMPLETE stop at a stop sign, and I may have passed a cop...on the outside of the lane...while exceeding the speed limit by quite a bit (not ticket... he just laughed). These are all things we could get a ticket for, but we kinda get a pass because we're on a bike.

And skidding the rear wheel is from Uniform Vehicle Code, not Georgia. Muh bad, y'all.
And I'm not actually a fixed-gear cyclist (clutch the pearls), I'm just reading a book on Bicycles and he Law, and the question popped into my head, so I asked it here.