So I'm not suited to follow your example, but I'm curious though, in terms of packaging banged up folks, do you apply the CID alone, or do you also apply some form of collar? Does it complicate or compliment what the EMTs want to do to these victims before air evac?
Well, I'm a trained First Responder and just about done with my EMT, need some more hours and that's finished, so it does not complicate anything. The CID i have is a basic set of foam tubes, it's good enough until someone with a properly sized collar shows up. You can make your own basic "CID"-y thing with a towel rolled into a "U" shap or just use kneel and hold - gently - the patients head so they don't twist/roll/move. Don't move. Did I mention that? The point is inline immobilization.
And out here, EMS response time can be 15-20 minutes, sometimes longer, so we more often than not are doing a lot of really basic stabilization and immobilization before the Paramedics arrive anyway. If they are alive when we get to them, all we need to do is keep things from getting any WORSE, but we don't make them BETTER.