I've been asked what should be done in a police encounter. I tell them that there are two guidelines to follow:
1. Be polite and comply immediately with the officer's directions.
2. If in doubt, see guideline #1.
The thing I saw more than any other was the person being arrested try to stop the arrest so they could 'explain'. They never seemed to grasp the idea that attempting to stop the arrest is resisting arrest, and no, the cop won't stop arresting you while you explain.
Best solution is to let it happen. You can explain just as well in handcuffs.