even if it might not be locked. it would need a requirement to be found, i wouldnt think it would just be needed to be a keyblade weilder. she wanted to protect ven and that included protecting him from mx.
i doubt anyone can just walk around there and stumble upon it
Another Report said:II – Worlds appear in KH. Could you please give an explanation of the means of coming and going between them?
Concerning the structure of worlds, first Sora and the Disney characters, and wherever we dwell, these so called “normal worlds” are attached to a World of Light. If all of these exist at the same level and you imagine them all sitting on top of a plane, there is also plane of existence on the other side where the World of Darkness exists.
At present, there are 4 worlds in between these planes that have appeared: A) Castle Oblivion, B) Twilight Town, C) Yen Cid’s Tower, and D) The World That Never Was. Constructed in this manner, Light < C < B > A > D > Darkness, you can imagine 2 planes with stairs ranging between the worlds. There are 2 means of transfer between these worlds, the first being the Gummi Ship Sora uses in what is called the “Sea of Outer Space.” In this way they can come and go between the worlds dotted through space. There is an invisible shell covering these worlds, so as to preserve the original world from interference from other worlds. By opening the hearts of each of these worlds this shell is broken and will become a group of shooting stars pouring down. Once settled, these shooting stars will become the Gummi Parts of the Gummi Ship. As they were originally from the shell covering these worlds, it becomes possible to interfere into each world.
I think some form of security was already taken according to this quote from Another Report. The Land of Departure was originally one of the "normal worlds" in the Realm of Light, so that it could be accessed regularly. Then somehow just by, using Master Eraqus' Keyblade on the World, it went from a world in the Realm of Light, to a world in the Inbetween Realm very close to the Realm of Darkness. So moving it to another realm and, changing the world entirely is pretty high measures of security. So I would assume that locking the Chamber of Waking would be important to the story, and therefor would have appeared in the cutscene, but it didn't so I don't beleive it happened.