I just wanted to share a story that one of my friends-DBAs shared with me.

So, they have internal DBAs responsible for the part of the environment and remote/external DBAs that look after another part of the environment.
In most cases these two groups do not look after each others environments and their responsibilities do not criss-cross. But my curious friend one day decided to do a little disk cleanup/checkup (from the old backups etc.) and discovered that archive logs for one of the mission critical databases have not been cleaned up for a year. The database was under the external group supervision.
After a short investigation my friend discovered that the database didn’t have backups for a year!

The moral is:
1) Even simple trivial tasks can sometimes help you to discover flows
2) Do not rely on third party contractors even if they have a very good reputation. Make an occasional checks. It wouldn’t heart to add a couple more servers to the monitoring.