The Opt-Out Reports for Pushpages indicate when a users has used the Opt-out link at the bottom of a Pushpage issue that they have received. This report shows the specific Date and Time as well as the issue they unsubscribed from and whether they elected to stop receiving Pushpages from just a single Distribution Group, or All Bulk Email.
It will not show those that have gone into their profile Settings > Notification and unchecked a particular Distribution Group.
The best way to see if a user is unsubscribed or opted out from a specific group is by going to the Distribution Group and clicking on Recipients. The Unsubscribed tab will show all users who have opted out of this particular Distribution Group, whether via the link in the email, or on their profile. The Opt-Out tab will show all users that have elected to receive no bulk email from your school, meaning they are unsubscribed from all Pushpages.