It perhaps shows how seriously MWM took the rules, i.e. not very.
This is insincere.
What Marc cared about was selling games. What Marc cared about was creating content. What Marc cared about was trying to breath some life in to the book of tables and figures.
The XBoat is supposed to give a feeling of what A society (and, inevitably, what THE society) would look like and how it might operate given the KEY constraint, in fact pretty much the only constraint on the society -- travel == communication.
The Pony Express is a romantic notion. It was dangerous frontier work. Folks willing to risk their lives to get the mail through.
How do you convey that in an interstellar society with abundant power and a galaxy of resources?
He could have just left mail to the Traders and Subsidized merchants. He could have kept Jump Torpedoes for the use of messaging. Disposable message drones flitting out every 15m, or whatever. But that's not what he wanted. He wanted the old empire, messaging is slow, ships are The Way kind of universe.
Once you have that vision, rules aren't that important, especially remote edge cases like this. It's all about feel.
It's hard to grasp how fast things were moving back then, how much stuff they were publishing, how fast they were publishing, and how small they were. We spend 30 years kvetching about things they decided in a microsecond so they could get something on paper and get the next product out.
That doesn't mean they didn't take the game or the system seriously. But they knew it was a framework, not writ in stone. And a 100 ton boat, gorged with drives, with some guy strapped in between the radiator and the alternator, committed to the premise of getting the mail through as fast as possible. Even when messaging takes a week, every minute counts, every dollar shaved on the ship and operation counts. Mail was not a
laissez-faire thing, it was social contract worthy of standing up something like the XBoat system rather than leaving to the whims of the Capt. Mals of the 'verse.