1) The master of the ship's internet-equivalent, probably
That isn't "knowing" something. That's believing it.
Yes, and both.
It is also possible to increase your jumping to such a high level that you jump across the continent in one leap. However, the spell wears off before you have crossed halfway, so you have to refresh it just before landing in order to not die on impact.
This viewpoint assumes that this convention makes it easier to communicate ideas. This is not true a priori, and certainly false for some conventions (that against splitting infinitives for instance).
In this case, I think you are wrong and that the convention is not sufficiently widely known/accepted to aid in communication.