I've been thinking about the role the fake Straw Hats might have in the future. But, as a wise person once said, we can't move forward without looking back. And I realized, they've already done all they need to do. All that is left is for Luffy to wipe the floor with them and then everything can be set into motion. Here's what I mean. People think the fakes are the actual Straw Hat Pirates, so much so that they've used their influence to recruit new members and strike fear into the citizens of Sabaody, as the Straw Hat Pirates. The real Straw Hats have had almost all the work done for them. The real ones come in, beat the brains out of the fakes, and take all the spoils. If The Straw Hat Pirates want to the world to know that they're back and better than ever, what better way than to burst in on the Sabaody scene, fight the impostors causing all the problems and be done in less than eight seconds, and then gain 100+ crew members in the time it takes Sanji to tie his shoe? Mihawk said that Luffy's most dangerous ability was the ability to make allies anywhere he goes. The people who signed up to join the Straw Hats are going to join the Straw Hats. And if you really want to make the Marines' heads spin, what better way to do it?
Officer :"Sir! The Straw Hat crew has been causing trouble at Sabaody again. Then the Straw Hat Pirates burst in, beat themselves up, and left a few hours later with 100+ people added to their ranks, some of them notable rookies!"
Fleet Admiral Aokanizu (all three admirals named combined): "WHAT?! Can you repeat that but this time make it less confusing?" (Who's on first? Yes. Who's on second? No, Who's on first.)
How much do you want to bet that's how the story will go down when the Marines catch wind of it? Luffy and friends will have reentered the pirate world with such a bang that it will make anything else that happens that day look like accidently forgetting to pay your bar tab (I'm talking to you, Nami!). But that's just me, what do you think? Are the fakes a blessing in disguise or just a minor annoyance?