If you've ever watched any shows with drunk people and the cops, such as The Real World, Cops, Beach Patrol, etc., you know there is never a shortage of people who when they get drunk, they think that they are smarter and more powerful than the police officer on the scene. They think that they can convince an officer to let them go free by threat or intimidation. And that if they keep back talking, somehow the officer will just give up and leave them alone. lol Even when sober friends beg them to shut up and things will be better, they fail to recognize that is a good idea. Eventually, they are arrested and even then they will sit in the police car and mouth off. I'm not sure what causes people to do this, but it's quite common.
I don't think Reese was all that bad in her drunken behavior, but still, I wonder why she kept getting out of the car, after the officer asked her not to. The charge will probably be dismissed down the road.