It is fair game to register whenever possible with your real id and when required with anonymity.

Unnecessarily placing orders leading them to believe you are a genuine is customer would be immoral though.

I had a hilarious incident when a new user signed-up & responded to my welcome mail saying, she is part of a stealth startup & needs guidance with choosing payment gateways. Silly part was her rapportive profile clearly showed her linkedin profile, that she joined competitor as product manager just a few months back. We had a hearty laugh & let it go.