I can't speak for other sites, but our site automatically updates every 10 minutes. Is it "real-time"? No, but very close. We have had two folks order the last of the same knife before. First order gets it, but site will not update for a few minutes, so second guy thinks it is in stock, although it was already sold (by minutes). The system is not perfect, but works well until something like this happens. Just a little illumination on how our site works.
md