You gotta be careful. Some interviewers, especially the ones who are going to be peers, or worse, a peer of the hiring manager, might have mixed incentives to avoid hiring someone who could show them up.

I feel that happened to me once when I was interviewed for a Java job at a stodgy health insurer and the interviewer tried to test my Java and it quickly became obvious he was really very much a Java beginner and I could run circles around him, correcting his misconceptions. I was polite about it but naive, and it quickly became obvious he was offended and gave inaccurate feedback.

Another job, one of my rounds was with a peer of the hiring manager, and he did not ask me anything really beyond introductions, and then he lied and claimed he had asked me several technical questions and I'd failed them, which did not happen. I got that job anyway and accepted the offer, which was a mistake.

So actually, you probably don't have to be careful, because this is a good way to avoid a bad job. Unless you're desperate and need to feed the kids or something. Then feel out the interviewer, and do well, but not _too_ well. Don't make the interviewer feel stupid. Save that for after you've been working with them a while and have built up social capital in the company.