Although, I will say that it wouldn't be unusual for someone to develop a website, roll out the entire project, but not allowed Public logins logins until they've had a chance to test it thoroughly. Most likely they would just have a secret user ID and password combination that they would use for testing purposes. Once they test it, publicize, let all of the preferred users no, then they could open the sign up to the target user set.
All complete speculation, but it happens all the time.