>>Robin8+(OP)
> Using the official HN API, the service fetches 90 Top Stories every minute and makes a comparison with the first 30 Top Stories (i.e. the Front Page) fetched the previous minute. It logs all missing Stories here. The assumption is that a Story cannot go from the top 30 to a position higher than 90 in a single minute, without having been explicitly removed.
The OP's hypothesis is that, if rank drops from top-30 to below top-90 (I think "higher than 90" is a typo?), in less than a minute, then it must be due to moderator action.
Is that true?