Well, in RP, a large part of rheinlands trade revenue comes from bretonians shipping military vehicles and engine components to the front line and the shipyards due to the invasion by kusari, so discouraging that would, in RP, do a lot more harm than good to the rheinland economy.
Seeing as (in RP) we can source those components and vehicles from liberty, loosing the trade would be a pretty big blow to the rheinland economy (mainly as it would boost the libertonian economy at the same time). So if you are trying to say that this is (in RP) a good move, id have to disagree.
Plus the definate prospect of being taxed by a government is much less inviting than the chance of being taxed by a pirate.