On the two occasions I failed to remove the large steel/titanium item in a piercing that set off the scatter machine so I was taken to a room and searched.
But the steel in my hands, the LED, chip and magnet in my left hand, the Vivokey and chip in my right hand - nothing. Even the handheld scanner doesn't pick them up.
One of the NFC chips was useful on my last trip to the US. I was constantly pulled over by the TSA and they might have wanted to inspect my laptop. So I made a backup, saved the minimum I needed, encrypted it on another device and uploaded to a domain. Clean installed the OS. The NFC chip carried a long string which to me gave the directory structure (very nested, no / in the string) and the encryption key. It wasn't needed, but it was amusing.
TSA scanners run around 30 GHz, which can only go ~1 mm into body tissue. It also isn't as high resolution as a camera, and objects a few mm wide won't get picked up well.
