Recording in public is 100% legal, you don't need the consent of the individual, despite what idiots like "catboy" think. What about CCTV? Cameras in ATMs? Recording a crowded street with all sorts of people walking by? Unless you are creeping on someone in a private place, there is nothing wrong with it. It's for educational purposes and to document your candid real life experiences.

I've had way better feedback on what I've been doing wrong on one video rather than I would have typing up paragraphs and paragraphs of field reports.