Board Thread:General Discussion/@comment-25417189-20150825221139/@comment-26940052-20150830133726

And if you dont believe then see the Omnitrix page of this wikia and search in "Trivia" the point were it clearly says:

" The new aliens weren't ever locked in the Omnitrix."

And is true, the term unlocked doesnt mean the same in Omniverse to what it mean in the another series, because Ben cant unlock the aliens, because he have access to all, but he can choose a new alien only taking his time to search him.