....or as my ol' man used to say back in the 60's --> "You can't fight city hall"
Most importantly, don't answer questions with statements....and don't make statements of fact ....you'll be convicting yourself. After your initial "Good day officer", and since the Supremes have said "Silence is a yes", your best reply is "Can anything I say be used against me?".
Like shik said --> make the courtroom your battlefield