Obviously a lot of their job involves flags, and he described a couple to me. No idea of any applications outside of these organizations, but I would expect from his description that motorcycle and car races in North America and internationally would use a similar set of flags if not the same. This is the only set of flags I can recall where this is the case.
Standing indicates debris on the track.
Folded, with upper fly corner to lower hoist, stripes vertical facing the riders, indicates rain. Standing means an emergency vehicle is on the course. Waved indicates the emergency vehicle is needed at that point. Race is stopped at once due to emergency. Pretty obvious to all.