No, that is not probable cause! The fact that this stuff is transported on the Planet Earth and the fact that you also live on the Planet Earth do not combine to equal probable cause.
"Probable" is the operative word here. What you are suggesting doesn't rise to that level. They'd actually have to show some conveyance, as they did in this case since they were able to prove that the order for the child porn had taken place. With that in hand, they knew the crime, i.e. his taking possession of the porn, was going to take place.
Your example is an unreasonable extrapolation unrelated to the facts in this case.