Unfortunately, it seems that some have the custom to make a list of track numbers of the coins they have seen, and pass these list to their friends, then they log as Discovered to have more icons in the profile.
I think most of the time this happens because of ignorance of the rules game.
My coin was also abducted from the first cache (one of mine) five months ago, however the bad news is that was abducted for a 'fellow' cacher that has her own rules, has no respect
We have had a great event in a sunny day, coins went quickly (next time I'll need more!), ...hunting for new caches in the wild prepared for the event with my own coins as prizes, ...a funny leap into caching
I have this coin, with a number that seems a tracking number, a combination of four numbers and letters with the prefix 2H (Two Happy Hickers).
Maybe were trackable long ago on another web, before the implementation of tracking in Geocaching?