I understand the question since I work in fraud and risk management. If you're doing this on a repeat basis you're going to get flagged because software is looking to detect anomalies and repeats in various data points.
I cannot think of a single legitimate reason to be doing this in a mystery shopping setting though.
For mystery shopping though, I do keep several different phone numbers and email addresses so that I can repeat calls and interaction with businesses without using the same identifying name and contact information.
What you're asking to do is borderline hacking in my opinion and could be illegal, depending on what you're doing and why you're doing it and how.