Username can be overridden until the account is active

While copy/pasting a system in which admin manually validates accounts, I just noticed that no error is shown when I try to register with the username I used just one test before. Indeed, the new infos I provide override the previous ones. Everything is fine once the user is active : the username is safe and can't be registered again.


But still, it's possible on the non-yet-activated ones. Can someone please indicate me how to prevent that ?

Is this when using the Register snippet?

Yes Susan