Why No Signal?

[NCHSAA]

In HS ball, especially here in NC, like BadNews said, it is expected that you stop the clock with the appropriate signal. I see it in college ball. I have always stopped the clock, as it helps to slow down and avoid the blarge. But some officials do not, which I think comes down to the particular play happening fast and the official reacting in the same way which helps to sell it also.