I don't know why this is such an unpopular idea. For comparison, people have implemented a "Proof of Humanity" system[0] which requires users to record a video

I don't know why this is such an unpopular idea. For comparison, people have implemented a "Proof of Humanity" system[0] which requires users to record a video of themselves holding up a key-derived number. This is very similar to my idea, except it relies on the uniqueness of faces rather than the cost of visiting a location. Both ideas seem imperfect, but obviously a system that links your ID to your face is less private than one which links your ID to a circle of radius 100 miles. It is also interesting to see that the system I linked to uses a "court" system among its members, where people are randomly picked to adjudicate claims about invalid IDs. There is even a system for claiming that a user has died and having their key revoked if they cannot prove they are alive. [0] https://www.proofofhumanity.id/ https://www.proofofhumanity.id/