In all seriousness about the color categories assigned: Since "they" will have access to credit bureau and credit card records and will be looking at past associations and purchasing patterns - will memberships in the NRA, purchasing firearms, membership in the American Border Patrol, etc. be considered risk factors and get a passenger put in the yellow category?
You will never know why it happened, but you will get extra scrutiny and each new Administration will be able to use the information in a political as well as a security manner.