It's an interesting thought ! Something like tourists to Vegas, taking home chips, never to be cashed. It's money loaned for free. Casinos shouldn't need new chips too often, but they appear. The USPS loves people that collect stamps, and hold them forever, as does the US mint.
Even better for offshores. John Doe dies, no trace of funds. Jane doesn't get the money. Even happens in USA, inactive bank accounts seized by states, 7 years I think. I brought this up with one of my banks. I have a tenant ( long-term). I hold a security deposit at a local bank. I make no transactions on account, eventually the state will take it. The solution is to update the book every so often, or depisit like $.01.
I'm sure books have profited by this, and will even more so in the future. The guy that hides it from the wife, or has no family is a prime example. In fact I've heard of books claiming the balance, after a peroid of inactivity.