Then the whole thing becomes meaningless. Oda made this scenario for a reason, and I doubt Garp will be the winner here.
I think Oda did this to show off sword and maybe show a rift in the marines .
Right now all marines suppose to be going to egghead preparing for war VS VP and SH .
So not only sword disobeying this order they also attacking a yonko on there own which also something you can't do .
Think this showing us that sword will play a bigger part in the final war than people think , when you have Kuzan say that sword group would not agree to BB terms.