To prevent fraud. It's the same reason governments have driving tests and tax or grant audits. If the government deferred to applicants for everything, there'

To prevent fraud. It's the same reason governments have driving tests and tax or grant audits. If the government deferred to applicants for everything, there'd be no point in the application process. Sure, there's a libertarian argument against limiting visas, imposing taxes, and issuing grants, but if you are going to, it requires some amount of enforcement to prevent rampant fraud.