This is strait out of the manual…

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This is for new hire exports where you only want the most recent offer to be returned.  Remember to set the ownerQuery name.

You are correct, normally a record that is dropped from a net-change data file will result in it being deleted or de-activated in the zone by following net-change run.  However if there was a net-change setup run before the next ‘normal’ net-change than this wouldn’t happen.   This is because the net-change setup will delete the current net-change data repository and then re-populates it with zone values, but only for those records in the data file.  I’ve recently written an example for this scenario that may make this more clear.
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