That's stupidly dangerous. People a) lie, b) are idiots, and c) continuously forget the most obvious things, like where we placed the glasses we're currently wearing. Often all at the same time.

Especially when stressed, for instance when about to get an MRI and being asked embarrassing questions, possibly while being high on whatever drugs they've got you on.

I'd expect them to at least use metal detectors.

Wouldn't want a doctor or nurse to get a prince Albert to the eye just because the patient was too embarrassed to mention it.