Then I would say that this would be a feature request. Being able to disable an account and maybe even control what email domains can be invited into “my data” would be useful.
Google Apps takes an approach to this problem that is interesting. They let you sign up as a Google app user with your company domain name but only a user who can prove that they control the DNS for that domain can “take ownership” and make system wide changes to Google App.
But in the meantime, janedoe@citichaseHSBC.com can start using their tools even if her IT department doesn’t even know about it. I think it is an interesting viral approach to user management.
I wonder if Paglo would benefit from this email centric approach to accounts.
Facebook and GetSatisfaction take similar approaches.
Just some thoughts.