I have been pondering this question, although in a more general sense.

How do the screeners even know the difference between normal human anatomy, an anatomical anomaly unique to the individual, an implantable medical device or prosthetic and a device implanted into suicide terrorist? Depending on the particular medical device/prosthetic and its location, a physician might be feel it through clothing, would likely be able to identify it if the skin were directly palpated and would undoubtedly identify it on imaging. But a screener...how do they know the difference between an implantable medical device and something implanted into a suicide terrorist -- and what would they do if they suspect the latter? When the passenger is saying "It's my prosthesis" but the screener thinks it's a nefarious device...is this when they call for a surgeon to break the tie??

I'm anxious to follow this conversation -- thanks for starting it!