How can I make Confluence reapply default group memberships for a user?

[Timothy Ford]

I would like to reset a user's status such that Confluence no longer remembers that the user has logged in.  The specific reason I'd like to do this is that I'd like Confluence to re-apply the user's default group memberships the next time he or she logs in.  Quoting from https://confluence.atlassian.com/display/DOC/Connecting+to+an+LDAP+Directory,

In Confluence 3.5.2 and later, and JIRA 4.3.3 and later: The first time a user logs in, their group memberships will be checked. If the user does not belong to the specified group(s), their username will be added to the group(s). If a group does not yet exist, it will be added locally. On subsequent logins, the username will not be added automatically to any groups. This change in behaviour allows users to be removed from automatically-added groups. In Confluence 3.5 and 3.5.1, they would be re-added upon next login. 

I would like to "reset" this so that the user will have the groups checked and applied on next login.  How can I accomplish this?

[Steve Thornhill]

Two ways spring to mind (neither ideal)

1 - Stop confluence and edit the users entries in the table to make them "look" like a new user

2 - Remove the user completely and re-add

Can you not just remove them from all unwanted groups and add them just to the default ones that are set up?