Would it make sense to add a column to pg_stat_database showing the total number of checksum errors that have occurred in a database?
It's really a ">1 means it's bad", but it's a lot easier to monitor that in the statistics views, and given how much a lot of people set their systems out to log, it's far too easy to miss individual checksum matches in the logs.
If we track it at the database level, I don't think the overhead of adding one more counter would be very high either.