I have been one of four ENG helicopters at a stationary scene where there was a search by law enforcement of a wooded area for an escapee. I can't imagine that many helicopters being involved in a chase sceanario. Strict adherence to altitude separation is not always as easy as it seems either, especially when there are law enforcement aircraft involved in the chase as well. The safest (and least expensive) way for everyone to get the shot is to pool the footage among the helo equipped stations, rotating aircraft. Some big headed news directors first have to get over themselves and stop having to be "First on the scene!"
My assignment 1995: Philadelphia (AS350BA)