In this case, I do not believe ether (wool or fleece blanket) by itself would have made much difference. Getting the people out of the wet clothing and into a warm ambulance was really the only way to prevent severe hypothermia. Blankets, whether wool or fleece will not be very effective, if the body is not producing heat and if the wet clothing is not removed quickly.

If, you are unable to remove the wet clothing and dry a person off, it is best to place a couple of hand warmers with the patient, wrap in a blanket (wool or fleece) and then wrap the person in a vapor barrier (plastic tarp, survival blanket, heat wrap, etc.). You will not be actively rewarming the patient, but will prevent further heat loss.

Pete