Randi - the scenario would be me finding a Registry error that a prior examiner missed- & then taking it to the Registry for correction  before turning the title in.  The prior examiner would be screwed to the wall because there's no way to establish a paper trail of the Registry's error.

Scenarios that come to mind are deeds out or easements affecting locus where the owners' names are misspelled and missed by the examiner.  In a few Registries here in Mass there's no real way to search by property address- everything is by name only and if the name is misspelled the Registry has to take it anyway.  

The other issue is the Registry having absolutely no liability for their errors.  I know someone who missed a small mortgage on a builder/developer where the Registry wrongly identified the property address.  Didn't matter that it was completely the Registry's fault - the examiner had a claim made on their E&O regardless. 

Years ago when we had paper indices the examiners would get certified copies of the index sheet; alert the Registry to the mistake and then enter all the info along with the certified index sheet into a private file that we maintained.  Not even remotely do-able these days.