requiresuniqueemail=true implementation in asp.net site
<p>Hi people I got a social networking site that is running live right now.The first time I launched my site I let requiresuniqueemail=false set-up on my web.config inorder for me to create dummy accounts for testing purposes and to start up the site you know.However the site is kind of stable right now w/ almost 5k members.So I would like to set-up the requiresuniqueemail to true so that users cannot reuse their existing email address and for me to make it sure that there will be unique email ad for each site user.I know the site got like 100 users with the same email address.My question is what could be the problem I'm going to face if I do this right now(requiresuniqueemail="true") and how to do this efficiently(without errors and if possible sitewide say in the global assax)?I tested and I already got an error if I logout an account.Like say a user try to click log-out this code runs:
<pre><code> Dim d As DateTime = DateTime.Now.AddMinutes(-1 * Membership.UserIsOnlineTimeWindow)
        Dim theuser As MembershipUser = Membership.GetUser()
        theuser.LastActivityDate = d
        Membership.UpdateUser(theuser)
        If Not Cache(Page.User.Identity.Name.ToLower() + "currentstatusnow") Is Nothing Then
            Cache.Remove(Page.User.Identity.Name.ToLower() + "currentstatusnow")
        End If</pre></code>
Then an exception occured on updateuser() function saying</p>

<pre><code>System.Configuration.Provider.ProviderException: The E-mail supplied is invalid.</code></pre>

<p>This is just one instance I know that I encountered a problem. Hoping to hear your ideas guys.....</p>
