For public ones, depending on what people started getting, it’d really strain the AIs. You could go in like 1 or two ways, probably different people getting both.

Something very uniform but still unique, like a QR code kind of deal, AIs would hallucinate the crap out of that. Or abstractions, like people do to change the way the shape of their face to combat facial recognition.

For private ones, just don’t ever get it photographed, any image showing that area without it would be probably fake.