[absolutelastone]

"Any evidence" is a low bar. Obviously there's evidence of many kinds. The point here regarding common sense is the evidence of human nature when it comes to lopsided risks versus rewards, and widespread knowledge of this imbalance. Legally proving fraud is obviously difficult in a world where there is almost no paperwork to go on (save what the applicant chooses to provide), and hardly worth the effort when the government can just stop investigating when it looks doubtful and reject the application for the same practical result. In the US most applicants are rejected and aside from obviously-suspicious ones who skip their hearing, the most common reason is literally that their fear isn't found to be credible. Also, a person who has multiple motivations but only lists the ones that would benefit them has lied by omission.