The G7 agreement has no bearing on US state taxes.
The latest Flag state ranking by Paris MOU proves the point:
PS> The White List contains 39 flag states. Denmark and Norway tops the list, including the vessels under DIS and NIS registers.
Pretty sure the same NIS and DIS vessels where inspected multiple times. Also, the percentages between the top 10 are so minor, when you also look at Fleet size vs Detentions/Inspections, it gives you a better idea on whom is actually the best. 5 of the top 10 largest registries (FOC’s lol) are in the top 10 of the Paris MoU (MI, Bahamas, Singapore, Greece and Japan). But again, they must be crap. 
They are not on ITFs list of FOCs (??)
By somebody’s thinking all flags but,… (add in your nationality) are FOCs and therefore the ships must be crap.
Run by greedy capitalists that care nothing about safety and their crews.
The ships are manned by uneducated “3rd World Villagers” that bought their tickets from corrupt officials.
Even worse; the ships may be built in China by slave labourers. “Everybody” know that such ships will fall to pieces within a year or two.
Notice how many FOC countries are strangely the home of tax evasion countries.
Fair enough, terminology I used was not on point. Tax haven would be more accurate. When it comes to hiding money South Dakota, Nevada and Delaware do pretty well but not on the scale of some of the FOC states. When I was young I was curious about why so many yachts had Delaware and Grand Cayman on the transom. Later I understood about Vanuatu, Marshall Islands, Panama, Belize etc. If you have billions it’s worth it to pay millions to hide the money. 