Hi. In the US, we now have electronic records that are available to all ER's immediately. It's almost universal in the US, in my realm of knowledge, that the first thing 1st Responders do when they find a person with death at or near imminent in their home, or work etc is check for DNR esp if they are seniors, disabled etc. They check the refrigerator, the purse/wallet as standard. They look for a DNR order. I keep copies of mine there plus I have a DNR sticker on my car dashboard. I notified my employer (HR) too. In the states I've lived in, this would be found and honored, no question. If I happened to cardiac arrest while shopping, I'll probably have some CPR done briefly before they find my paperwork in my purse/wallet. But I won't continue along that route for long. ER's would check for DNR too + get it immediately upon EHR search bc they are filed with your Dr or health system. They're accessible across the US.
I also have an Advanced Directive that details other medical measures prior to CPR also to be withheld. They are different documents, but for me, they work together to allow for a natural death with dignity.
A bracelet isn't a legal document + can't be construed by medical or law enforcement personnel as such to withhold CPR. But it does tip them off to hurry + search your wallet or fridge for a legally executed document to provide direction to them for what legally they can not do. Certain emergency providers must follow the law, and in the absence of a legal DNR, they can't make their own decision not to perform resuscitation.
I'm not a lawyer. But this gives you some information to research.