Some have emailed me asking why Ricky was running with RED numberplate backgrounds at A1. After some digging I found this from the AMA:
Jan 11, '07
AMA rules, including reigning champions must display red number plates
Pickerington OH: AMA Racing has implemented a new rule requiring red number plates be displayed by reigning champions in the Ampd Mobile AMA Supercross Series and AMA Toyota Motocross Championship presented by FMF. This will help identify the current champion if he elects not to use the traditional number 1.
The champion in the Supercross and Motocross classes will run a red plate with white numbers. The Motocross Lites champion will display a red plate with black numbers.
Teams were informed of this change last fall during a series of meetings held at AMA offices in Ohio and California. The change was also reflected in the 2007 AMA Supercross Series/AMA Motocross Championship Rulebook which was made available at the end of November.
Ricky Carmichael debuted his red plate at last weekend's Ampd Mobile AMA Supercross Series opener in Anaheim CA. Carmichael is also the reigning AMA Toyota Motocross Champion and will continue displaying a red plate when that series begins on May 19-20 at the Hangtown Motocross Classic in Sacramento CA. Ryan Villopoto is the reigning champion in the AMA Motocross Lites class and will also run a red number plate.
Other changes implemented for 2007 include new fuel testing procedures; lowered sound limits; and new licensing criteria and qualifying procedures for both motocross and supercross. Riders are also now required to be equipped with an emergency helmet removal device.
Courtesy AMA