Sometimes we don't need to apply Web firewall rules to everyone that uses our site, because we trust in the users of certain group, for instance, users that belong to Administrator or Publisher groups. Or we have a Buyer group and we want that users of this group are not disturbed. This is why we have created this option. Here you can see the groups to which to want apply the rules:
If an user belongs to several group, rules will not be applied if there is, at least, one group marked to No.
Despite of having this type of 'privileged' users, we can see a log of the trusted entries on the system selecting the option 'View trusted entries':