Joab, I don't think it's enough of a precedent to be worth worrying about. How many thieves would be happy to wait 50 or 100 years or more so their grandkids could profit?
I imagine that whoever took the 1933 coins just couldn't stand to see such beautiful coins destroyed...
It's been too long since I was a vest-pocket dealer, but I recall seeing a proof of the first Double Eagle. Sometime in the middle 1970s. It was reputedly taken by a director of the US Mint, back in 1850 or whenever. Nobody was all that excited about it. The asking price was $4,500, IIRC.
Art