I know a young man who shot a deer thinking it was a legal doe. Shot it at a distance with open sights. When he retrieved the deer it had spikes about 3 and a half inches long. 3 inch spikes would be legal, he was fined $300.00 for that. He probably won't ever hunt again, just because of that heavy of a fine for a half an inch. That was in Missouri.
Sounds like to me, that guy got off cheap, Part of hunting is identifying your target as legal.
As for the improperly tagged deer, it probably depends on whether or not the hunter had a valid permit to hunt deer or not. Seems the person who's tag he used would be up for a fine too. Here's a list from 2011 on fines and penalties for game violations.
"where'd you get the gun....son?"