If Barack Obama tried this he would soon realize his own impotence to enforce such an order.  This story is perhaps put out by gold sellers trying to push huge premiums on numismatic coins?

I agree John. As Bob Chapman and Robby Noel often point out: even if they did do so, they wouldn't get much gold or solve anything for themselves. Furthermore, the $100 that Roosevelt let you keep is the equivalent of about $10,000 now (i.e. the present worth of four $25 gold pieces of that day). There is indeed no danger of a gold confiscation from the general public. What they WILL do is try to get everyone with significant wealth to disclose their gold holdings so that they can then tax it as a capital gain. So there's never been a better time to dig deep hole out in the back 40 somewhere rather than storing where there is a paper trail. But it has nothing to do with confiscation.