In my experience (200+ interviews conducted), it's very rare to see somebody with an obvious "interviewing skill". Actually, I should qualify that. I've seen a lot of people try. But giving wrong answers with conviction and enthusiasm is not really a skill. Among smart candidates, I haven't seen much fakery.

What I'm looking for, and that's also what I wrote, is that candidate has put some effort. This can also be in getting to know about the company or in updating his/her CV. There are candidates that are so fond of themselves and their perceived technical skills, that they act like diva's and don't find it necessary to put any effort. I'd rather not have those as my colleagues. I'm not saying that not preparing automatically means the candidate is such a diva, there can ofc be many other reasons, but it's an indicator to be alert for.

And again, this is not the only indicator I'm looking for. A candidate who didn't prepare much but can tell very enthusiastically about some project or technology is obviously motivated as well.