If you create a custom email when you distribute a survey, then this change affects you. Qualtrics has added an opt-out link to all email distributions.

Even if you’re good at sending survey invitations without being irritating, some of your panelists may want to opt-out and some emails may bounce. Those who choose to opt-out will remain in your contact list, but they will be flagged as “unsubscribed.” Knowing how to manage and limit bounces and opt-outs is an important part of panel management.