Great question, and the answer is "they won't". Unless your State/Local LEO's have loads of cash to spare, dumping your phone is magical movie stuff that they simply can't do. I have the equipment, and still need PINs/Passwords unless you mind waiting weeks for a cracker to hack through the password (assuming it's not last on a pile needed for drug/murder cases). Also, I don't know of any on-site EMT that will grab a USB thumb drive off of a victim and plug it into any work computer (that's how virus's are spread, ask the Iranians how they know).
A laminated card somewhere on your person, or attached to your gear (AeroStitch and others make gizmos for this sort of thing) works, as does a simple set of dog tags (working for your DOD since, well, forever).
My 2 cents, YMMV.