I carry one on my key ring only because it has been there for about 36 years now. It is getting work kind of thin too.
Re EMS personnel and handcuffs, please keep in mind that the "patient" is in cuffs for a reason. Many had to be fought to get them cuffed, often by more than one officer. Removing cuffs without A LOT of good guys around can have things go bad in a hurry. Personally, I never left a cuffed suspect alone with any medical personnel. I caught him, and I keep him 'til he is in a cell. The only exception might be for an x-ray, then we would try to switch to hospital hard restraints, but I would be there when the cuffs were removed...
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OBG