Assuming we're talking about mid-career professionals. The fact that someone is invited to the interview means that you liked CV. Now the task is to ensure that CV is truthful - by discussing previous projects, experience...

After this discussion, if the interviewer is unable to tell whether the candidate is lying or not about his past experience - this means he shouldn't be interviewing in the first place.

And there is one thing to remember - false negatives, i.e. skipping over good candidates, is very expensive. Big G might ignore this fluctuation, but it is much more crucial for those wannabe-be-big-G startups who mimic even how interviews are held.