I reported this sorry tale to Groundspeak (contact@geocaching.com) back on 26th May, and enquired whether GS could/would take any action.
They thanked me for the information and promised to investigate the matter.
By 22nd June, I had heard nothing further, so I asked Groundspeak for an update.
I received the following reply.........
Thank you for your response. I do not have anything further to report. It doesn't looks like the player has logged onto the site in over a month. Hopefully a warning was all they needed.
If you have any further issues with this user, please do let us know.
So, if all 42 coin owners were to e-mail Groundspeak, then "something" just "possibly" "might" "perhaps" be done.
But don't hold your breath!
Try not to let your mind wander...........
It's too small and fragile to be out by itself