Intotrials is right. Some parts of the bike can still be moving forward whilst the wheels are momentarily stationary. Try holding the front brake on in the garage, press down on the bars, and the body of the bike moves forwards. Rotation of the front wheel would not work if that became the criteria - it could easily stop turning when clear of the ground, attacking a step, for example.
Every time the referee blows the whistle at a football match there are contrary opinions as to whether the decision was good. Observers are instructed to be consistent at the pre-SSDT briefing. However, they, like football referees will all see things with a slightly different pair of eyes, so consistency between observers (referees etc) is more difficult to achieve.
Regarding an earlier point about not revealing your scores when asked - this is impossible because the rider (or a friend) simply looks over your shoulder when you are writing the next score down.
Regarding another earlier point, rearranging sections is not on. It's the same people all the time, so at least you know when to be on high alert!