How bad does it have to be before the "special deletion" clause is invoked when a user is removed?

Question

Why do I have a reputation change on my reputation page that says 'User was removed'? Includes the following:

This removal occurs whenever a user is deleted, unless that user had a very high reputation score. Because high-reputation users have usually cast a great many votes, removing all of them could be that much more disruptive to other users. In such cases, the staff use a special deletion that preserves the votes, resulting in no reputation change for those who had been voted on by that user.

Recently it seems we had a user removed that affected a LOT of the sites most active users. Apparently that user's rep was not high enough to trigger the above mentioned "special deletion." Yet by observing the rep changes for the Month of May, the deletion of a user put around 540 different users into negative rep territory for the entire month overnight between 5/24 and 5/25!

Although the user that was removed apparently did not have a high enough reputation, the number of vote reversals affecting over 500 users indicates it was fairly disruptive to the community as a whole.

Answer 1

Normally there is a time period after which things lock in as well. The problem here was that it was an extremely prolific voter on a great many sites, so the account deletion resulted in a large amount of reputation change across the network.

This wasn't isolated to just Photography. 3 out of 4 sites I moderate had meta posts about this event and are in similar states. My best guess would be that this user was using just about their full up vote allocation daily across much of the SE network.

This meta post covers more from SE on the subject, not that there is much more to say.