Arrived a bit late on this one(strong headwind!) but lots of interesting points. When I started Police flying 3 years ago I was told that the observers weren't part of the crew. As with Skycop and many others, I'd always flown as one of two crew.
As the unit Flight Safety Officer, I teach Flight Safety and CRM on our Unit's Observer courses, emphasizing that they are 'part' of the aircraft's crew, and how to assist in aircraft emergencies.
I was too late to read Chiplite's entry(it had been deleted(I wander why!!)), but from Hunter Delta's comment about the course length then Chip was probably right. My unit's courses are usually 3 weeks and we've just managed to cram one into a fortnight!! They fly one sortie each of Urban Nav, Crime Search and Vehicle Pursuit and that's it. No time to consolidate, so it's very much on the job training. Not the best way, but I suppose it all comes down to money these days.
May the Force be with you!!