I don't see how you make the leap from "open borders" to "no borders" ... "open borders", without putting words into Carrol's fingers, doesn't mean an open field where people come and go as they please. It means an immigration mechanism that doesn't rely on qualifications ("Must speak English!" or "Must not be Submissive Woman!") or quotas: if you want to become a resident, here's a form and a process; if you want to become a citizen, here's a form and a process.
It doesn't mean getting rid of a "border patrol" ... quite to the contrary, it makes it more important.
/jordan