There have been plenty of restrictions throughout history, and those who didn't meet the requirements were deported. https://papers.ssrn.com/sol3/papers.cfm?ab

There have been plenty of restrictions throughout history, and those who didn't meet the requirements were deported. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2301603 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2301603