Domain User -creating personal domain without the user opting for it.

Settings on my site for Domain User

Domain User Module -enabled
Module behavior:[]Ask users if they would like to create a domain
Content editing forms: *[]Show user their publishing options
Permissions :Auth User-Create Personal domain
-View Domain Publishing

The users account page shows []Yes,I want to create my own site at username.domain.com

But ,even when user clicks save without selecting this option a subdomain is created.
The same thing occurs if user changes his username and clicks save without enabling the 'create my own site option.

Anyways,Its not a botheration becuse the user can change his username and thus his subdomain name too along with that.Just bringing into your notice.

Thank you.