They should forget the age thing. Let the market decide, let the parents and kids decide what tournament type to enter. In FL. many tournaments now have choices depending on the demand.
For example, last weekend we went to a tournament that offered Orange Ball G 10s and B 10s. Yellow ball G 12s, B 12s, G 14s, B 14s. No red or green, just orange and yellow because the tournament director did some trial and error and found out those offerings drew kids.
The orange 10s had some little tikes, some very raw, some very good. A few kids were in the yellow ball 12s that had no business playing yellow yet and they lost 6-0,6-0 in the 1st round. But thats the parents call to put them into that.
The market will decide. Offer the red or orange or green or yellow as the specific market demands. Train the beginners using the red, orange, yellow system in a lesson setting, then let them play the type tournaments they want.
The Norcal rigid age deal is just wrong. A good coach will produce sound players and a bad coach will produce bad players, no matter if you force kids to use red, orange, green, or not.