I recently did the care flight trauma course, Talking to the instructors ASNSW has recently started suppling them to crews again, One comment that was made was they have become more popular since the Afghanistan campaign and also a new surge of research in to the effect on them has shown them to be a valuable tool in trained hands.
I recently used an improvised one at a competition, when the judge questioned my use of it I pointed out that as long as I could tell exactly when I had applied it and why there should be no problems, And as an aside we never got penalised for using it
Maffu