If a person has a responsibility to recognize property rights, other responsibilities come into discussion. It's really a simple concept that American-style libertarians don't fully comprehend.
Objectivism and related strains of philosophy simply can't establish an ethical purpose behind unrestrained property rights without deferring to stupid arguments like 'Lockean land acquisition' or 'God-given' bla bla bla. What constitutes authentic ownership over land and resources - which are necessary to produce labor and capital - are highly subjective.
At what point does property become yours? If you mix your labor with the land? So no natural preserves? If you bought or traded the item? So does that include items stolen 30, 40, 50, 100 years ago? If you sign a contract but are under the influence of drugs, are you obligated to comply? What if you're 14? Autistic?
Large government arose alongside capitalism to monopolize on these questions and thus allow finance to prosper. The only small governments left in the world are communal and tribal; the state became the strong-arm that forced people to recognize property rights, debt obligations, tort law, and other things. I don't much care for the discussion about 'large' or 'small' anything because I'm a small d democrat that wants to see individual and group sovereignty take hold foremost.
