After a lead unsubscribes from an email in a workflow, what happens to the rest of the workflow?

After a lead unsubscribes from an email in a workflow, what happens to the rest of the workflow?

I created a drip campaign in Campaign Workflows.  We are sending it out to a specific group of leads.  One person in the list appears to have unsubscribed to several of the emails in the drip.  Shouldn't the first unsubscribe have stopped the rest from going to his/her inbox?  Or is that something I need to add to the drip?