If you add another Worlds player to collaborate on your world, they will be able to interact with the world in new ways without requiring additional permission from you, and may be able to build, edit and change anything in that world, including things that you and other collaborators have created. Adding someone as a collaborator may also allow them to use the Import World function to copy your world into another world (that you might not have access to). Once the world is imported, they can modify it as they want and even publish.

Only grant collaborator access to people you trust.

If you delete your Meta, Oculus, or Facebook account associated with Meta Horizon worlds, and do not specifically delete your worlds before deleting your account, others you have invited to build your worlds, if any, may assume management of them under certain circumstances. Any items within the worlds, including any voice recordings you upload using the Sound Recorder, may continue to exist in those worlds unless and until those worlds are deleted. Even if they persist in the world, any voice recordings you have created may no longer be associated with you or your account. If you do not want your collaborations with other Meta Horizon worlds players to exist after you delete your account, you should delete those worlds or items, or remove all collaborators, prior to deleting your account.