Via Boingboing, a fascinating array of tricks of the trade for a plethora of trades. One that is patently wrong -- at least in Ontario -- is the paramedic quote:

When paramedics arrive at a car crash or similar accident, they very, very rarely announce any casualties at the scene—almost all deceased will be pronounced “dead on arrival” at the hospital. This is because it involves about 10 times more paperwork to announce someone dead right in situ than it does to say they expired in the ambulance on the way to the hospital.

When I worked as a volunteer ambulance attendant on the Emo ambulance crew, we had strict guidelines that dictated when a patient could be determined to be dead at the scene (transection, decapitation, rigor mortis to name a few). Otherwise, we were required to transport and attempt to resuscitate the patient en route to the hospital.
However, DOAs do require a heavier paperwork load -- regardless of your region.