At a fundamental level, whether or not you should clean it up depends on one key ratio. That ratio is the danger that it causes related to the time and effort it would take to clean up. If the data being there is largely innocuous, and it would take a lot of effort to clean it up, then you leave it. On the other hand if the data is deadly to the task at hand, and it's easy to clean then obviously you do clean it up.
in reply to How Software Engineers Are Different Than Auto Mechanics
The tipping point should be determined by the load on the bandwidth of the people who can clean it up. If they're all straight out with no bandwidth left, then it will take a lot more danger to get it cleaned up.
My mission: To boldy split infinitives that have never been split before!