>If they don't have probable cause to DETAIN me (ie, pull me over and prohibit me from going about my lawful business), then it is illegal.
>
>>No, they have to have probable cause to search you or your car. They can stop you any time they want.

Asking you what country your from is not detaining you. Ever cross the border from Mexico into the US? The Border Patrol agents
ask that question all the time. It's perfectly legal. If after answering they suspect you're not legal, they can arrest you. How is
that different in San Diego from AZ? It's not. It's perfectly legal for the authorities to stop you and ask where you're from.