If you come to an intersection with a stop sign, and there is no traffic coming, do you run it? If you had run a stop sign because you could clearly see "No one was coming!", do you think you would get off, or be able to argue this "on principle"?

Now youre in a school zone, but you think you can go faster than the posted limit because, "Theres no children out!"

Do you see a parallel?

You were in a school zone. There were signs posted that said "school zone" and gave an acceptable MAXIMUM speed. You exceeded that. You are expected to obey laws, not make judgement calls on them and form an opinion as to when it is the correct time to follow them. Theyre not called "guidelines"