That is why we have roads and whatnot. Although I don't think it would be legal for someone to buy land around me to prevent me from leaving my home without trespassing. Real estate has laws regarding that, normally with a shared walkway or whatnot.
Don't apply principles that belong to individuals to the state. The land of the US is not directly analogous to the "backyard" of the federal government, if that is where you are going with this. Think of how much they could limit the freedom of citizens if that were the case.
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