Police stop driver for drifting in lanes on highway. She admits to having glass of wine at family party, but she left after argument with her mother. Police allege she fails field sobriety tests and she refused post arrest breath test. Barracks equipped with video recording of booking process, but police fail to preserve and save recording for trial. Defense requests instruction from Court that Jury can draw adverse inference against government for failure tor preserve tape. OUI charge dismissed by prosecution after jury selection.