Cesar, no watch. Had I worn a watch, I probably would have scared myself with the pace I was seeing and ended up slowing down, possibly giving away the win.
As for the mile markers, I don't know what the case was with them. I think the first “5 mile” marker was just a misplaced marker. It was only about 1/4 mile short of the 4 mile marker so it was too far in to be at 5K. My take is that the guy on the pace bike was probably wrong about the 3 mile marker being 3.5 miles, that first 5 mile marker was just a misplaced marker, and the rest were probably about right. I kind of assumed that on the course by the time I was a distance past the 4 mile marker and still knew I was over a mile from the finish but there's always a bit of uncertainty in the middle of a race when you're so focused on just running hard, your brain has shut down a bit, and you just need more than anything to get to the finish line before you run out of gas.