Problem with Union in Registration further complication?

[Bleep]

Hi. I know the problem with adding union in the account creation area is well known and documented. However, I just realized that if someone tries to create a page with union, it acutally creates it with the supplied email. This prevents someone from creating an account with that same email again. Maybe this is well known too, just wanted to put it out there in hopes there might be a temporary workaround till the bug is fixed. thanks.