In my neck of the woods, the police don't even normally think to check for the 'dog tags'; since they're the first responder for most 911 calls, and for any "found a person unconscious" call (or 'sick passenger on the train'), I'd recommend the bracelet, which they WILL check for. EMS will probably check for the tags - but if the PD finds the bracelet, they'll note it in the call, which means that there'll be less delay once EMS gets to you.