Yes, it is only possible to access drafts created by other users if they have been saved in a space to which you have access. If the user saved the draft in his/her private personal content, you will not have access to it.
How to access drafts from other users?
When doing a search, you can
filter
by 'states' and selectdraft
Users can grant your access to a specific Story
They can invite you to contribute to a draft (or a published Story)
💡 Note
Visibility of drafts from other users is particularly helpful for co-creation.