What happens when I add a collaborator to my world in Facebook Horizon?
If you add another Horizon player to collaborate on your world, they will 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 also allows 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 someday you delete your Oculus or Facebook account, and do not specifically delete your worlds before deleting your account, your worlds will automatically transfer to an existing collaborator of those worlds (making the collaborator the creator). Any items within the worlds, including any voice recordings you upload using the Sound Recorder, will continue to exist in those worlds unless and until those worlds are deleted. While they will persist in the world, any voice recordings you have created will no longer be associated with you or your account. If you do not want your collaborations with other Horizon players to exist after you delete your account, you should delete those worlds or items, or remove all collaborators, prior to deleting your account.