Keep in mind that a single spaceship wouldn't take up the whole beam - for one thing, there would be a bunch of them, and for another, we simply can't focus a laser on something the size of an iPhone from even as far away as the moon. That said, it is still a massive amount of power that needs to be reflected.
I thought this also, but "[...] to keep the beam tightly focused on one probe at a time would require [...]" in the original article points in the opposite direction.
