You provided 2 news articles about 2 specific incidents. None of the news stories that you link to provide any indication whatsoever that students game the legal immigration system whatsoever. The document I cited gives specific numbers of authorized v/s unauthorized immigrants giving an idea of the scales we're talking about.

Its pretty clear that you've made up your mind about what the state of the world is (from various anecdata) and don't really care what the statistics really say. I will leave this as my last comment about this issue.