That's an interesting thought! The problem is that the "attacked" country could just seize the homes for themselves in a moment - you end up just giving an eno

That's an interesting thought! The problem is that the "attacked" country could just seize the homes for themselves in a moment - you end up just giving an enormous fortune to your enemy. The only way it would work does would require quite the conspiracy: thousands of buyers of homes colluding in secret over many years without raising suspicions, until the other country is weakened by decades of poor housing and then striking before they have a chance to pull the rug.