I see some weird stuff in Florida and normally the cops just let things go, especially in the Miami area. I would say tripling the passengers to amount of seats is normal here, hacienda ride they call it. That being said, the cops know that if 12 people are in the car / in the Miami area, 1 is packing a gun / 1 has drugs / & the cops are looking for a problem.
I'd say the racial pullover reason is the highest probabilty, bar none.