Yes, but the handoff can fail in the same way (it can't know if the thing it's handing off to actually got it). But the application can also just be resilient to that with idempotent operations and have the handoff be at-least-once.
Everything in a digital system can fail, but by convention (and because it's not so far from the actual truth) some parts are assumed to be 100% reliable when modeling them. If you don't make this assumption, you can't guarantee anything.
