What are the mechanics of this ban? I see student was denied from connecting flight. What happens if said student travels to, I don't know, Germany first. Spend

What are the mechanics of this ban? I see student was denied from connecting flight. What happens if said student travels to, I don't know, Germany first. Spends there a day or two and hops on a flight to US of A? I ask because I understand ban is for admission of refugees and travellers from seven countries. Not nationalities.