And no doubt all the holders will rush to turn in their gold.
Not so much. And if they come door to door for it, they will get a lot of lead and copper mixed in.
They don’t have to physically take your gold to prevent you from using it.
A goodly chunk of merchants will be unwilling to accept illegal gold, and a goodly percent of them would be quite happy to turn you in as a hoarder.
And then there’s the reward money...
Every gold based transaction is an opportunity for public excoriation, fines, jail time or a lethal firefight.
That tends to chill the market a bit, no?