I would say that in most cases,
…while you are on your own as a small soul fragment (part of your Higher Self), either on the astral plane in your astral body or in one of the physical universes incarnated with a physical body,
…the Higher Self allows you to do whatever you want to do on your own and experience the manifestation of your own personal reality bubble. And also so that you as a fragment can develop true free will against the game’s artificial input and limitations.
All data and experiences collected through you is uploaded into the Higher Self the moment the experience is made.
There is also a big hidden intelligence that is also part of the total of you, working in the background to make your experience as a soul fragment possible – the subsconscious mind. But it is much more complex and fragmented than that…
From time to time the Higher Self may intervene (mostly with the help of other of its soul fragments, which are often your “spirit guides”) in order to save you from doing big uncessary mistakes like killing your body before your time or repeating the same experience for another 20 loops etc. (= helping you to avoid the long detours inside the game).
Why is the Higher Self doing this?
Because it is not like that it would be pleased to play this game forever and ever. It wants to see and experience all the exciting levels and stuff and then move on to another game. No fun to be stuck in some boring side quests and levels or doing the same experience 5000 times when 50 times are enough…
Of course, different Higher Selves also play the roles and different characters inside the whole game (different alien fractions, different beings and creatures, the “good” and the “bad” guys etc.).
To answer your question:
Everyone manifests their own personal reality bubble up to the point where beliefs and game rules are agreed to be shared with other players. In most cases other players can not do anything that you have not manifested. And if they can, then because your Higher Self allowed this to happen in order to collect a particular experience.
Again, personal opinion only