That's not really how it works. Nobody's out there 'approving' research (well, not seemingly small projects like this), especially at the university level. Professors (all the way down to PhD students!) are usually left to do what they like, unless there are specific ethical concerns that should be put before a review panel. I suppose you could argue that this work should have been brought before the ethics committee, but it probably wasn't, and in CS there isn't a stringent process like there is in e.g. psychology or biology.