For specialist roles and experience, I'd definitely interview differently. Hard to do live coding there, but if you can tell me exactly about how you've solved problems in the space, that's awesome.
Most of where I've see the "how would you manipulate this array" type of stuff is generalist stuff or new-to-the-particular-subdomain candidates, where if I asked for exactly what I'm looking for them to know, they'd fail. Gotta just look for people who can learn it on the fly fast instead, and I haven't found any better proxies yet. :|
