When Watchlist checks are enabled, due to the extensive nature of the databases which are checked it is possible for a visitor to be matched as a false positive. These false positives are typically for US Government issued notices regarding services such as the Department of Health and Human Services, and other related service exclusions.
In the event that a visitor is reported to be found on a watchlist erroneously and should be removed, and has permission to "Invalidate Security Checks":
Navigate to the visitor's profile, and click on the "Security Checks" tab, then click on "Offender Match", or the "Details" link to display the match result:
Click "Mark Invalid":
The visitor ban will automatically be removed, and the record for the security check will now display "No Match (Invalidated)":
Note: the watchlist result will be retained, however, the visitor will no longer be prevented from accessing your locations.