There are some studies that claim a large percentage of people (40%+) lie on their CVs. As someone who hasn't done that and struggles to lie even in games, I have a hard time believing it. But even if 5-10% of people lie, hiring is a lemon market, and you definitely don't want to get stuck with the lemons.

Most lying is apparently to change start and end dates of previous employment to cover up short stints where they may have been fired for poor performance, but even if work samples/skill tests/structured interviews were 95% effective, you would still regularly hire duds.