This isn't to take too seriously, as I don't really know if it was intentional, but I believe I found a controversy. Now, ye pirates should know of Blackbeard's flag as seen in one of the scenes on the Queen Anne's Revenge. After looking at some On Stranger Tides-related images, I noticed something rather odd that I don't believe has been brought up as of yet: Barbossa appears to be using Blackbeard's flag!
Evidence of said claim being the following images(well, image, as it's pretty much the same scenery):
What's really intriguing is that this very brief shot of Barbossa's "Calico Jack" flag was used at the beginning of one of the featurettes for On Stranger Tides(Blackbeard, Zombies, Mermaids, to be exact).
Having said all that, I'll say now that I came up with two possibilities: either Barbossa has truly begun using Blackbeard's flag, or the very slight chance that this was a "movie mistake". I'd choose, but given that this was practically unnoticeable, I think it'd be best to see if Barbossa truly changed his flag in the potential Pirates 5.
So what do you all think? Would Barbossa have taken Blackbeard's flag(as he already claimed his ship, crew, and sword), or would he have kept his old pirate flag as he supposedly kept his old pirate regalia?
One small detail I may have overlooked, which definitely deserves to be said(thanks to HephaestusThePrivateer). Barbossa's flag can be seen in the Black Pearl in the bottle...this screenshot, to be exact.