Visitors enter event passwords in two places: on the password page of a protected Event and on the Event Access landing page. To keep somebody from guessing passwords, Event Gallery counts the failed attempts per IP address for one hour.

The IP address itself is never written to the database. What is stored is a SHA-256 hash of the address combined with the secret of your Joomla installation, together with the time of the attempt. Rows older than an hour are deleted whenever the next attempt is recorded, so the table only ever holds the last hour.