My FD has been against red lights (what's allowed here) in POV's for many years. We regularly see motorist who are ignorant to the rules when approached by red lights and sirens on authorized emergency vehicles, never mind "courtesy lights". Having served in both an all volunteer FD that freely issued permits for POV lights, we routinely got complaints about fireman driving like idiots. Take out the red light and you have just another person driving like an idiot.
As courtesy lights do not allow any violation of the law, the only thing you gain is clearing traffic in front of you. This becomes very confusing to motorists at STOP signs and red lights. Do they go? Do they pull over? Do they even see you? It's far more clear when you have a siren and are legally "pushing" down the left side. How much time can be saved if you're merely travelling the posted speed limit?
I made a run as an off duty chief one day to a mutual aid tech rescue call. I ended up following the fire chief from the VFD we were assisting. He had a light bar but no siren, and the confusion was ridiculous, he finally pulled over and let me lead with fully audibles and lights to clear the traffic. He went out the next day and bought a siren as he said his choice was either remove the lights or buy the siren.
Sorry, but I can honestly say that courtesy lights have far more liabilities than benefits.
I was going to ad to this however I think Adam hit everything right on the head. Back when I used to volunteer I wouldn't run a light for exactly that reason. I would rather be thought of as an idiot driving fast than a part of the fire service. In my state technically the only purpose of the courtesy light is to allow you access to the fire scene other than that its just confusing and dangerous.