> There is a way to weed out the liars - you hire them and then when it does not work out you fire them.

In my experience, firing someone takes multiple months. Months in which they are mutating the codebase (with review, but it's a time sink that shouldn't exist for a decent senior), influencing other engineers, etc.

Passing on a good candidate is cheaper in the long run than hiring a bad candidate. Or said another way, false negatives are preferred over false positives.

> You would be astonished how little people lie on their CV.

This has not been my experience. From something as white-lieish as "I designed and implemented" vs. "I was a peer on the team that did it" to flat out fabrications. You learn alot by simply asking "what was your role on the project" and asking follow-ups to dig into their contributions.