There is no need to know much about immigration laws to successfully navigate the US immigration system. All you need to know is that CBP has the power to deny

There is no need to know much about immigration laws to successfully navigate the US immigration system. All you need to know is that CBP has the power to deny entry for any reason whatsoever, and the best way to avoid triggering that code path is to have your papers in order. Have an outstanding visa application? Reentry visa expired? Passport expired? Lost your copy of the I-20 form? It's very simple, just don't travel. It doesn't take a supreme court justice to know this. It's inconvenient and cruel, sure, and it could use reform, but it is what it is.