I doubt it'll be of any use though if such a situation were to arise. They'll most likely still try and resuscitate me, completely ignoring my explicit wishes
An EMT will look at your bracelet, see that it does not contain any relevant
medical information (diabetic, epileptic, etc.), and ignore it. In an EMS situation, they couldn't care less about your living will or advanced directive.
Only an official DNR, clearly posted near your body and fully and accurately completed would be recognized and heeded.
Look at it from the EMT's point of view: we arrive on scene, we don't know you, we have no idea whether you wanted to die, or whether someone has attempted to murder you, or whether you were messing about with erotic asphyxiation and went too far, or accidentally overdosed, or what the hell happened. You can't honestly expect us to take at face value a piece of paper saying, "please let me die!", can you?
I really don't mean to be nasty about it, I just want to point out that EMS has what is typically a really shitty, really high stress job, where we see too many people die who desperately want to live. When we arrive on scene, the last thing we're going to think is, "hmm, I wonder if we should just let him die? Does anyone see a note that will protect our decision of inaction in front of a courtroom full of lawyers and bereaved family?" It is completely against all our training and all our professional experience, never mind our legal liabilities. And statistically speaking, we're doing the right thing when we try to save someone's life.
It sucks for we miserable few who want to end our lives, but that's just the way it is.