While I can't say anything from the prospect of an interviewer, as an interviewee I am a big advocate for this style. Give someone a set of requirements, and then talk through how they would solve it. Allow for further clarification, and just talk about tech. It's a little more unstructured and less formal, but surely you'll very quickly pick up what experience they have, whether or not they've made past solutions that'll fit, what new technology they'd like to use, what technology they'd end up actually using, and there's no set right or wrong answer. The interviewer might even end up learning about something they themselves weren't aware of.

If someone could blag that while not being able to even write FizzBuzz, all I can say is well played to them.