Louie once bubbled...
Education - for divers and non-divers
Regulation and management of wrecks
Policing and monitoring
Reality check everyone, WW is right, only education is realistic. I have a real world example for you that happened in our neck of the woods.
Background info: in the great lakes we have hundreds of acres of "underwater preserves", that is, anything on the bottom of these preserves is protected by law and is not legal to even touch.
Segue to the Manitou preserve in lake Michigan. About six years ago we had an especially rough winter season. A large sandbar off one of the Manitou islands was erroded away. In it's place was found a previously uncharted wreck named the "Three Brothers". Nothing special as wrecks go but it was new and had many good 18 hundreds era artifacts scattered about and on the deck. This wreck is less than 50' off-shore, started in about 15' of water down to about 55' of water. It is easily accessible from the island but the island, which is smack-dab in the middle of the preserve, is quite a distance from the mainland and therefore only accessible by boat.
I was lucky enough to dive it several weeks after is was discovered and saw a lot of artifacts. A month later most of those artifacts were gone.
This wreck was managed and regulated by the underwater preserve already established. It didn't change a thing.
This wreck was policed and monitored. In fact, it doesn't get any better than this. There is a staffed ranger station, complete with boat right on the island, not a half a mile away from the wreck. It didn't make a difference.
Where there is a will, there is a way. Many of us who have been diving for years originally got into diving to recover artifacts from underwater. It's the way it was, totally acceptable and a normal reason to dive. Bottom-land conservation is a relatively new thing in our area, gaining steam in the last ten or fifteen years.
I'm not condoning wholesale stripping of wrecks, quite the opposite, i agree with and follow the laws of the underwater preserves but would like to point out there are extremes on both sides.
Case in point the Neo-nazi conservation officer who tried to ticket a friend for picking up a bottle from an inland lake which was not part of any underwater preserve. Thank gawd a reasonable state police officer happened by and talked the CO out of the ticket. The CO really wanted to haul my buddy in to jail for picking up this bottle which by the way was trash with no significant age value whatsoever. I'm not sure but i don't think Mickeys Malt Liquor was around in the 18 hundreds ........lol!
Be careful what you ask for, you just might get more than you desire.