Without a national government formulating a protocol and deploying executive personnel on your behalf, you have to go to your national border yourself and keep an eye on who enters your country and why, wouldn't you? Question would be: on what protocol?

If you don't want to do that because you don't want to work as a border guard or civil servant, but would rather do something else with your life, then you have to agree to a protocol and a border staff deputising for you that subjects the border to your living space to an order that does not stress capacity and social reasonableness. This staff must be trained and paid. Since this executive personnel is state-run, it is therefore subordinate to the government.

Unless you don't want a national border at all. In that case, however, you have to accept that you are thrown back on your immediate surroundings (house/apartment) and thus on your own skin.
This is because your immediate and wider surroundings can then be entered arbitrarily by anyone and you cannot automatically assume the exclusive goodwill of all people. The same would happen if you had no government. Your world would then be reduced to a much smaller space, as you would have to start joining forces with the people you know in your neighbourhood, i.e. form a kind of citizen militia. But you wouldn't know whether the citizen militia fifty kilometres away from you would follow the same rule, etc.