I figured out a way to make my recent thought experiments on the Berlin Wall even starker.

Suppose you wake up one day and find yourself in a cage.  You see a guy on the other side and the following conversation ensues.

You: Any idea how I got in this cage?

Guy: You’re not in a cage.

You: What do you mean?

Guy: You’re outside my border wall.

You: [stunned silence]

Guy: You’re free to go wherever you want, as long as you stay out of my territory.

You: I’m in a cage; where am I supposed to go?

Guy: Not my problem. After all, I’m not keeping you in; I’m keeping you out.

You: So it was you that built this “border wall” last night?

Guy: Yep.

You: And everything on the other side of these walls is your legitimate territory?

Guy: By Jove, I think he’s got it!

You: So you built a tiny square wall, and that entitles you to virtually all the land on Earth?

Guy: What, are you a communist?

You: No. You’re a kidnapper.

Guy: [offended] How so?

You: You make up a ridiculously lax rule of property acquisition, then use this sophistry to imprison me.

Guy: [offended] I repeat: To imprison you, I would have to hold you in. But I’m not; I’m keeping you out.

You: Pure sophistry! All you have to do to claim the world is build a tiny fence and say, “I own everything except the area inside it”?!

Guy: Well, what’s your theory of property?

You: I never worked one out. But yours is crazy.

Guy: Most of the people around here support me.

You: But plenty of them don’t?

Guy: True, but it’s a democracy – and the majority voted that you’re not allowed on any of our land.

You: I’ve heard enough. I’m climbing your “border wall.”

Guy: Communist!

You: You seem like the communist to me. I’m getting out before you start shooting on sight.

Guy: Good idea!

You: [facepalms; flees]