From Detroit Free Press:
LANSING — When Nancy Prins sent the Michigan State Police a Freedom of Information Act request in July 2008, asking for police video of her May traffic stop, she was told it was not available because the department only keeps such videos for 30 days.
A few months later, when the seat belt case involving Prins and her passenger came to trial in Ionia County, state police introduced the video of the traffic stop as evidence.
So, Prins sued State Police for violating the state FOIA law. She lost her case in circuit court, but won on appeal.