Heavy security surrounded the conference centre during the morning's proceedings with venue bosses having banned the use of amplifiers in the car park following a request from Labour.
During the test, Ms Witherspoon refused to heed the officer's request to stay in the car, saying she was a "US citizen" and had a right to "stand on American ground", the report is quoted as saying.
At 3.30am on the day she died, the court heard, Mr Burrell was seen by a policeman loading his car with Diana's possessions to destroy - something he said was at the request of the family.