A databases of incidents where the company was at fault might be useful, but not of staff. It just couldn't happen for so many reasons.
Companies do need to get a grip.
Unfortunately some staff who have a history of incorrectly charging customers actually get
promoted. For example, the Guard who made incorrect claims and charges in the
zzip00 incident, has been mentioned by many other people as rejecting valid tickets in a wide variety of incidents (eg. "Route via Peterborough" tickets claimed to be invalid via Peterborough) and also rejecting staff travel passes, yet was
promoted to a "Minder Guard".
Something needs to be done to deal with staff who bring the industry into disrepute, the companies are reluctant to do anything about it, but this isn't the solution.
I don't think we'll
ever see a solution, sadly. The train companies don't see it as an issue, and there is no organisation that can make them do anything that has the willpower to do anything.
So the incorrect charging and rejecting of valid tickets looks set to continue indefinitely.