[AFAIK]

Could someone explain the process in a little more detail please? If one of my factories or properties is sitting idle would someone have to serve me notice about their intentions to take ownership and give me an opportunity to justify my continued ownership? If so couldn't I argue that I am using the buildings/ machines as a store of value and intend to use them as a medium of exchange in the future?

If there are no legal tender laws then I could argue that all my possessions are money.

[Eran]

Legal rules regarding abandonment would exist, or quickly evolve.

I don't see the situation as being materially different from what it is today. There would be a presumption of abandonment after certain number of years of unuse and neglect.

Continuing to keep up the premises would be a clear sign that they weren't abandoned, as would be a claim against trespassers.

Remember that all enforcement is initiated by property owners. If a building appears abandoned, and no regular subscription is paid to a private police/insurance company to keep out trespassers, nobody will stop them from moving in.

Such squatters, however, would live, for a while, in legal uncertainty, as the original owner may, at any time, come back to enforce their rights. After certain time elapses, the burden of proof would shift from the squatters to the owner to demonstrate why the property should not have been deemed abandoned.