User blog comment:Tpetrillo05/Plots for P5/@comment-1984959-20121023063300/@comment-1984959-20121024160043

'Tis only speculation based on their own imagination/small hints they were given. For about 3 years, folks believed the fourth movie was going to be titled "Pirates of the Caribbean: The Fountain of Youth" and that it would start with Jack and Barbossa meeting in New Orleans. All that went down when Depp himself appeared at the D23 Expo and announced On Stranger Tides, and months later(shortly before production began) some Disney exec(I think) clarified that the New Orleans idea was false and they didn't came up with that synopsis.

My point: don't count your chickens before they hatch. ;)

I know it's not for certain that atlantis will be in pirate 5 but we have came to conclusion about that.
 * No, you came to this conclusion based on speculations made by others. Right now, I'm neutral on the debate on if Atlantis would be in P5 or not. It's possible, but there's currently no proof aside from fan speculation.