How many times have you gotten a ride with a friend? Are you going to peer around in their glove compartment? So even if you're just in the car, maybe even barely know the people (i.e. after a party, getting a ride home from the club, friend of a friend taking you all out to a restaurant), and one of these people, maybe even someone you don't even know, has drugs on them, you're going to jail. The whole car load of people are arrestable now. Scary.