EDIT: Turns out that it is possible to get the loot out far enough for it to be unretrievable - you get teleported back before you can reach it. So, this exploit is still an issue.
You know when you have people who think, "If I can't have my loot, then neither can you" and they sail into the Red Sea and sink with their loot?
Well, have no fear. Don't follow them in far enough to take damage yourself. Just watch them sink, and then swim out to gather it. You don't take damage from the Red Sea when swimming in it.
You may encounter sharks, though, so come prepared.