Real conversations escape the tool. A prospect replies to your colleague, books a call on your calendar link, or tells you at a conference to stop emailing. The campaign, knowing none of this, carries on to step three.
You can now set a lead's campaign status directly — mark them engaged, completed, unsubscribed, or cancelled — from the campaign log, with the same transition validation the automatic paths use, so you cannot create an impossible state.
Available through the API too, which is what you want if your CRM is the place these events actually land.