I think that in the next few chapters we're finally going to see Bellamy's assassination attempt on Luffy, but Barto will notice it first and block it with one of his barriers.
Then he'll probably go absolutely psycho on Bellamy, leading to Luffy reprimanding him, and thus begins the downward spiral of Barto's fanboyism.
Speaking of Barto, can I make a prediction that he will end up an antagonist? Because;
Barto has idolized Luffy ever since he first witnessed the failed execution in Logue Town, following every news and update in regards around the villanous Strawhats and Luffy in particular, fanatically looking up to his accomplishments. But who is to say that what he knows about Luffy is in the slightest bit true fact? Apart from the first bit, what he likely has followed is the image portrayed on luffy, by the goverment and co. The deeds done and reported have been briefly viewed to be twisted into facts picturing the Strawhats as all else but good.
I think of the example back when Zoro read a newspaper concerning Enies lobby being utterly devestated at their hands, followed with a very aggressive declaration of war against the entire world. Barto has to all likelyhood followed those same news and viewed Luffy in his perspective as a hero. However, he is about to meet Luffy in an entirely different light than he expects and when he does realize Luffy is not at all what he has been led to believe, come to a crashing dissapointment.
"meeting your hero is not always a good idea" for many reasons, especially when you used official news to draw an expectation of the guy.
I hope I havent repeated what someone else has suggested already and if so, I apologize.