According to the rules, this is a false start.
Any movement in the SET position is a false start. Period. And in 2012, this is an automatic DQ. No second chances.
Today, officials are using the sensors on the starting blocks to detect any pressure, and if there is pressure before 0.100 seconds, then it is called a false start. See Marvin Bracy 55 meters 6.08 Video: A False Start?.
Even a genetic freak with a real reaction time (RT) of 0.0991 is considered a false start, and we have proved that is possible! See Changing the IAAF Reaction Time Rule .
In the video, it is clear VCB is using a rolling start to get momentum coming out of the blocks. But she does it without triggering the sensors. The official should have asked the runners to “stand up” and issue a warning or even a disqualification (DQ).
Here is the video on YouTube.
How Does She Do It?
First, this practice is risky and can lead to a false start, and thus a DQ. (Am I repeating myself here? Am I repeating myself here?)
You can accomplish this by having part of your toe (or tip of your spike) on the track, with the rest of the spike on the blocks. This is how I recommend people use starting blocks in The Rocket Sprint Start.
By leaning forward, any of the weight changes will be on the ground portion, and not the sensors.
But this is technically a false start as you are moving in the set position.
Kids, don’t try this at home.