Have you ever worked with mechanical turk or anything of this sort? You pretty much have to do at least 15 minutes of manual moderation per day. Training "human workers", setting up rating templates, finding human mental "bugs", i.e. things that raters/moderators get consistently wrong - it takes quite a lot of time.
Granted, not everyone does that, someone nibbling at the frontend or sitting deep in some distributed DB generally does not care much about data quality.
Granted, not everyone does that, someone nibbling at the frontend or sitting deep in some distributed DB generally does not care much about data quality.