I write the owner's names and the last sharpening date on the blade plates with permanent marker.
I started doing it for Synchro, because they tote all the team skates together and it's too easy to get them mixed up.
It's handy for sharpenings as well, since the skates have to go off-site.
Rubbing alcohol is what I've always used to remove permanent marker, even from skin. Just never use it on finished wood - it melts the finish.
I keep nail polish remover in the house, and not rubbing alcohol. Does rubbing alcohol work for sharpie on transparencies too? I've always used nail polish remover for that too.
For transparencies, you should use Vis-a-vis markers. They wipe off with water.
I'm always out of nail polish remover, which is odd since none of us wear nail polish. The kids get the manicure bug and change the polish daily for a while, until we run out of remover, lol.
FWIW, I would make him earn the blades by proving that he's earnest about skating.