PassagePoint's watchlist is a quick way to add a visitor/host to a BOLO (be on the lookout) list.
When a visitor/host is registered, and a match is made, the matched watchlist is brought up as a pop-up.
To configure and turn the watchlist on, see here:
The "Disallow Sign in" stops a visitor from being signed in, if a watchlist match is made
However, it is possible that the match is a false positive, in which, the "Override Sign in" can be used and an "Override Password" can be added. This allows the front desk person to make that judgement call and be able to sign in a visitor when a false positive occurs.
When signing in a visitor that is on the watchlist, The Override password panel comes up and the password must be correct in order to continue.