I'm not sure if I completely agree with "Except in reality, you don't."
In some sense I enforce ownership of my house just by living here. Someone is here most of the time. The lights are on. There is activity. That keeps others out.
If I just abandoned the place, eventually someone might poke their head in and see if there was anything to take. Sure, that would be illegal, but the cops aren't going to post a guard for me under most circumstances.
You actually see this happen in downtrodden neighborhoods where whole blocks get abandoned. In theory that property is still owned by someone, but without anyone actually there, eventually houses get stripped of valuable goods and in some cases squatters move in.
https://en.wikipedia.org/wiki/Defensible_space_theory is an academic theory of this point of view.
Another good example is house sitters. When traveling for extended periods of time, people will let trusted 3rd parties stay in their house for free. Why? Enforcement of property ownership.