I work in the information technology profession. I am attached to financial and legal systems. One thing that is very important to do when you are testing systems or processes is to make sure that your test is coordinated or completed in a separate environment than production. In addition to that very obvious requirement, when you are testing you should let all of the relevant people know that you are testing, what you are testing and how long you will be testing. So ideally, your test should be imperceptible by your business partners and stakeholders. But in case it's not, you should communicate that the anomalies they may experience are part of a test. If you don't take these steps then your customers and business partners may experience or see changes and lose their religion. They will do things like calling your boss in a panic, escalating the "problem" to department heads or on-call production support, or worst of all, contact people like CIO's, partners, executive vice-Presidents, the IRS or other law enforcement.
It's probably better that the last group of people doesn't know your name, if it's being mentioned along with some sort of production meltdown or apparent criminal activity. So again, to avoid all of that unpleasantness, you should let people know what and when you're testing and what the expected results are. Unfortunately the Michigan Democratic Party forgot this basic concept in its zeal to do battle against hacking.