Now let's say I steal your chair. This is the moment in our narrative where we get to see whether you and I live in a society that adheres to the property principle.
If I steal your chair, and everyone gets sort of angry with me, and I say shove off and sit on my new chair, then we live in a society where the property principle is at most weakly enforced.
Let's say I steal your chair and get arrested. That implies that there are police, who are funded by some kind of entity which has taken it upon itself to enforce property rights. Which means that the means by which property becomes a real social fact is force enacted by, say, the state, against those who choose to disregard the principle.
Thus in a society where the property principle is taken for granted, that principle is in itself upheld by the implicit threat of force.