While I understand the reasoning behind the Elusive Firefighter, I think the example is rubbish. Set the license limit to MAX_INT. Surely two billion licences should be enough, and the problem is solved (with a high degree of confidence) within minutes. I don't know the codebase, but disabling checks may also suffice.

Depending on the company, refactoring legacy code is like walking through a minefield to get to a territory that isn't really desired by the higher ups. High cost, low reward.

As for the rule "If you see something wrong fix it properly!" I disagree in some cases. If you are a legacy maintainer, usually something is broken and management/clients want it up ASAP. The proper fix is rarely the fastest. Beyond that, you have to be careful when advising refactoring. If you advise it too much, in cases that don't really need it, management may not take your advice as seriously when there really is a problem.