Running red lights - an off-duty police privilege?

From Slashdot, an interesting look at whether Dallas police officers should be able to run red lights even when not on emergency calls.

As with many other jurisdictions across the country, Dallas employs red light cameras to help reduce traffic accidents across the city. It's a decent idea, given than as many as 22 percent of all accidents are caused by drivers running red lights (see Howstuffworks article). Emergency vehicles are obviously exempt from both the cameras and from red light when on emergency calls, but what about when police officers are simply on patrol?

The Dallas Morning News reports that the Dallas Police Department will require officers to pay the $75 fee if they run red lights in non-emergency situations. Many of the officers have bridled at this policy change, arguing that citizens want them to be able to arrive at any site as rapidly as possible.

Should officers always be exempt from red lights when on duty? In marked or unmarked cars?

I've seen police officers in my city flick on the emergency lights to simply avoid long light cycles at a left turn signal. Perhaps I'm just bitter at being left behind at the light, but I feel like exemptions from traffic law are for on-the-job duties, not just a fringe benefit. Then again, maybe they were on a call. But then, why not keep the lights on? Thoughts?

Note: see some comments here - some thoughtful, others inane.