What's with the lights?

This is might seem a little bit off topic, but I thought that I would get other people's perspectives (including those of you who have worked in pre-hospital EMS), and I will bring it back to an ethical issue.

Why do AMR rigs drive with lights and sirens on?

At least in Seattle, Medic One provides first responder care to patients. The premise of using lights and sirens is that rapid arrival on scene of an incident will help to decrease mortality in emergent situations (although even this premise is debated). Since telephone triage is not 100% effective, unless it is absolutely clear that there is not a life threatening situation, Seattle Fire responds with lights and sirens going. And when it is clear that a life hangs in the balance, Medic One comes along with similar displays to encourage the motorist (as well as pedestrian and bicyclist) to move out of the way. Once on scene it is determined that the patient does not need ACLS certified transportation to the hospital, AMR (a private company providing ambulance transport in Seattle) is summoned. At this point someone (a paramedic or firefighter, occasionally via telephone conversation with a physician) had determined that a life threatening emergency does not exist and that the patient does not need to be transported post-haste to the nearest emergency room. Yet, AMR will arrive on scene with lights and sirens going.

For anyone that has witnessed the number of near miss accidents of been in an emergency vehicle rushing through a busy city, it is apparent how dangerous it is for the operators of the emergency response vehicle, let alone the citizenry. Despite this, someone has decided that it's okay for AMR to drive as fast as possible to a non-emergent scene. How does one balance the ethics of this response with the danger it exposes everyone too?

Just as a clarification: this is not to say that certain AMR rigs do not transport critically ill patients. Indeed, AMR in Seattle has pediatric critical care and adult critical care vehicles that provide inter-hospital transport (and occasionally from the helipad at Harborview to another hospital). Usually this is done without use of lights and sirens, as even though the patient is sick, they are already receiving appropriate care.

I have some ideas behind this, but wanted others to weigh in first.