Lets assume a libertarian paradise. I am the owner of several million acres that is adjacent to your million acres.

We don't have "citizens" but instead the people living on our land are more like "clients". They pay various fees for services we provide and generally this works pretty good.

Obviously security and protection are one of those services....however for whatever reason.... you allow unvetted people to enter your land. Upon realizing this, I concoct a plan: Whenever I have a habitual criminal in my area, I pay them a stipend, provide them travel, and escort them to your side of the border. Since I have "vetting process" for the people I allow on my land, those criminals are not allowed to return.

Its a good solution for me since its the most cost effective way for me to "export my criminals" to you. Sucks for you and the clients that live on your land as now they are going to experience more property / violent crime.

You should probably be sued by your clients....Ideally you should go out of business....